| | |
| | | <template> |
| | | <div class="chapter" num="4"> |
| | | |
| | | <!-- 第四单元首页 --> |
| | | <div class="page-box" page="120"> |
| | | <div v-if="showPageList.indexOf(120) > -1"> |
| | | <h1 id="a008"><img class="img-0" alt="" src="../../assets/images/dy4.jpg" /></h1> |
| | | <h1 id="a008"> |
| | | <img class="img-0" alt="" src="../../assets/images/dy4.jpg" /> |
| | | </h1> |
| | | <div class="padding-116"> |
| | | <p> |
| | | 知识改变命运,技能成就人生,全社会坚持尊重劳动、尊重知识、尊重人才、尊重创造.著名厨师厉恩海曾是一名军人,练就了一身拉面绝活,他能把1 |
| | |
| | | <div class="page-box" page="121"> |
| | | <div v-if="showPageList.indexOf(121) > -1"> |
| | | <div class="padding-116"> |
| | | <p class="left"><img class="inline2" alt="" src="../../assets/images/xxmb.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="inline2" alt="" src="../../assets/images/xxmb.jpg" /> |
| | | </p> |
| | | <div class="fieldset"> |
| | | <p>1.实数指数幂.</p> |
| | | <p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | |
| | | <!-- 115 --> |
| | | <div class="page-box" page="122"> |
| | | <div v-if="showPageList.indexOf(122) > -1"> |
| | |
| | | <h2 id="b022"> |
| | | 4.1 实数指数幂<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <h3 id="c034">4.1.1 有理数指数幂<span class="fontsz2">>>></span></h3> |
| | | <h3 id="c034"> |
| | | 4.1.1 有理数指数幂<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"> |
| | |
| | | </math>.例如,2就是8的立方根. |
| | | </p> |
| | | </div> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 一般地,如果<i>b<sup>n</sup></i>=<i>a</i>(<i>n</i>>1,<i>n</i>∈<b>N</b>),那么<i>b</i>就叫作<i>a</i>的<i>n</i>次方根. |
| | | </p> |
| | |
| | | <!-- 116 --> |
| | | <div class="page-box" page="123"> |
| | | <div v-if="showPageList.indexOf(123) > -1"> |
| | | |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>116</li> |
| | | <li>数学.基础模块</li> |
| | |
| | | <mn>3</mn> |
| | | </math>. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 在初中,我们曾学习过整数幂的相关知识.<i>a<sup>n</sup></i>(<i>n</i>∈<b>N</b><sub>+</sub>)称为<i>a</i>的<i>n</i>次幂,<i>a</i>叫作底数,<i>n</i>叫作指数. |
| | | </p> |
| | |
| | | </p> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"><img class="img-gn1" alt="" src="../../assets/images/gn.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/gn.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block">分数指数幂</p> |
| | | </div> |
| | |
| | | <!-- 117 --> |
| | | <div class="page-box" page="124"> |
| | | <div v-if="showPageList.indexOf(124) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="t0">学习过的整数指数幂的运算性质就可以推广到有理数指数幂.</p> |
| | | <p class="t0"> |
| | | 学习过的整数指数幂的运算性质就可以推广到有理数指数幂. |
| | | </p> |
| | | <p>设<i>a</i>>0,<i>b</i>>0,<i>m</i>,<i>n</i>∈<b>Q</b>,则</p> |
| | | <p> |
| | | (1) <i>a<sup>m</sup> a<sup>n</sup></i>=<i>a<sup>m+n</sup></i>; |
| | |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p>1.填空题.</p> |
| | | <p>(1) 16的4次方根为_____;</p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <mroot> |
| | | <mn>16</mn> |
| | | <mn>4</mn> |
| | | </mroot> |
| | | <mo>=</mo> |
| | | </math>_____; |
| | | </p> |
| | | <p>(3) -13的5次方根为_____.</p> |
| | | <p>2.计算.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mroot> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mn>3</mn> |
| | | </mroot> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mroot> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mn>4</mn> |
| | | </mroot> |
| | | </math>; |
| | | </p> |
| | | <examinations :cardList="questionData[124]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <msqrt> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>a</mi> |
| | | <mo>−</mo> |
| | | <mi>b</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>a</mi> |
| | | <mo><</mo> |
| | | <mi>b</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>;(4) |
| | | <math display="0"> |
| | | <msqrt> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mn>3</mn> |
| | | <mo>−</mo> |
| | | <mi>b</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>b</mi> |
| | | <mo>></mo> |
| | | <mn>3</mn> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>;(5) 5<sup>-2</sup>;(6) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>. |
| | | </p> |
| | | <p>3.用分数指数幂的形式表示下列根式.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mroot> |
| | | <mn>9</mn> |
| | | <mn>4</mn> |
| | | </mroot> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mroot> |
| | | <msup> |
| | | <mn>6</mn> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mn>5</mn> |
| | | </mroot> |
| | | </math>;(3) |
| | | <math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mroot> |
| | | <msup> |
| | | <mn>3</mn> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mn>4</mn> |
| | | </mroot> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p>4.化简(式中字母均为正实数).</p> |
| | | <p> |
| | | (1)<math display="0"> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mn>0</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <msup> |
| | | <mi>b</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>a</mi> |
| | | <mi>b</mi> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>. |
| | | </p> |
| | | </div> |
| | | <h3 id="c035">4.1.2 实数指数幂<span class="fontsz2">>>></span></h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p> |
| | | 小学我们学习了自然数,初中从自然数拓展到整数、有理数乃至实数.类似地,在学习有理数指数幂的基础上,我们可以将<i>a<sup>x</sup></i>中指数<i>x</i>的取值范围从有理数拓展到全体实数,此时,<i>a<sup>x</sup></i>的意义是什么呢?如<math |
| | | display="0"> |
| | |
| | | </msup> |
| | | </math>,它们是一个确定的数吗?能否计算出结果呢? |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 实数指数幂 事实上,我们可以通过科学计算器计算出<math display="0"> |
| | | <msup> |
| | |
| | | <!-- 119 --> |
| | | <div class="page-box" page="126"> |
| | | <div v-if="showPageList.indexOf(126) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | <!-- 120 --> |
| | | <div class="page-box" page="127"> |
| | | <div v-if="showPageList.indexOf(127) > -1"> |
| | | |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>120</li> |
| | | <li>数学.基础模块</li> |
| | |
| | | <p> |
| | | 所以, 2<sup>0</sup>+2<sup>1</sup>+2<sup>2</sup>+2<sup>3</sup>+…+2<i><sup>x</sup></i>=2<i><sup>x+1</sup></i>-1. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p>1.计算.</p> |
| | | <p> |
| | | (1)<math display="0"> |
| | | <mn>16</mn> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>27</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>0.001</mn> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>3</mn> |
| | | <mrow> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mo>+</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mo>×</mo> |
| | | <mroot> |
| | | <mn>9</mn> |
| | | <mn>3</mn> |
| | | </mroot> |
| | | <mo>×</mo> |
| | | <mroot> |
| | | <mn>27</mn> |
| | | <mn>4</mn> |
| | | </mroot> |
| | | </math>. |
| | | </p> |
| | | <p>2.化简(式中字母均为正实数).</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mi>b</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mi>b</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <msup> |
| | | <mi>b</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>·</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mn>2</mn> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <msup> |
| | | <mi>b</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <mroot> |
| | | <mfrac> |
| | | <msup> |
| | | <mi>b</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mi>a</mi> |
| | | </mfrac> |
| | | <mn>3</mn> |
| | | </mroot> |
| | | <mo>·</mo> |
| | | <mroot> |
| | | <mi>a</mi> |
| | | <mn>3</mn> |
| | | </mroot> |
| | | <mo>÷</mo> |
| | | <msqrt> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mi>b</mi> |
| | | </msqrt> |
| | | </math>. |
| | | </p> |
| | | </div> |
| | | <h3 id="c036">习题4.1<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p>1.选择题.</p> |
| | | <p>(1)(<i>a</i><sup>-2</sup>)<sup>3</sup>=( ).</p> |
| | | <p>A.<i>a</i></p> |
| | | <p>B.<i>a</i><sup>-8</sup></p> |
| | | <p>C.<i>a</i><sup>-6</sup></p> |
| | | <p>D.-<i>a</i><sup>6</sup></p> |
| | | <p> |
| | | (2)<math display="0"> |
| | | <msup> |
| | | <mn>16</mn> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>. |
| | | </p> |
| | | <p>A.-4</p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <examinations :cardList="questionData[127]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <!-- 121 --> |
| | | <div class="page-box" page="128"> |
| | | <div v-if="showPageList.indexOf(128) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <h3 id="c036">习题4.1<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p>2.计算.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mroot> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mn>5</mn> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mn>3</mn> |
| | | </mroot> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mroot> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mn>4</mn> |
| | | </mroot> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <msqrt> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>m</mi> |
| | | <mo>−</mo> |
| | | <mi>n</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>m</mi> |
| | | <mo><</mo> |
| | | <mi>n</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>;(4) |
| | | <math display="0"> |
| | | <msqrt> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mn>4</mn> |
| | | <mo>−</mo> |
| | | <mrow> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (5)<math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>25</mn> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>;(6) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mn>0.125</mn> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (7) |
| | | <math display="0"> |
| | | <msup> |
| | | <mn>16</mn> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>×</mo> |
| | | <msup> |
| | | <mn>64</mn> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>×</mo> |
| | | <msup> |
| | | <mn>32</mn> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>. |
| | | </p> |
| | | <p>3.化简(式中字母均为正实数).</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <msqrt> |
| | | <mi>a</mi> |
| | | </msqrt> |
| | | <mo>·</mo> |
| | | <mroot> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mn>3</mn> |
| | | </mroot> |
| | | <mo>·</mo> |
| | | <mroot> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mn>4</mn> |
| | | </mroot> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>9</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <msup> |
| | | <mi>b</mi> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>6</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>⋅</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mi>a</mi> |
| | | <mi>b</mi> |
| | | <msup> |
| | | <mo stretchy="false">)</mo> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3)<math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mi>m</mi> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | </mrow> |
| | | </msup> |
| | | <msup> |
| | | <mi>n</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>÷</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mi>n</mi> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p>1.计算.</p> |
| | | <p> |
| | | (1)<math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>2</mn> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>×</mo> |
| | | <msup> |
| | | <mn>4</mn> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>×</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>2</mn> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>×</mo> |
| | | <msup> |
| | | <mn>4</mn> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>;(2) 3<sup>-2</sup>×4<sup>4</sup>×0.25<sup>4</sup>; |
| | | </p> |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>25</mn> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>27</mn> |
| | | <mn>64</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>. |
| | | </p> |
| | | <p>2.化简(式中字母均为正实数).</p> |
| | | <p> |
| | | <math display="0"> |
| | | <mo stretchy="false">(</mo> |
| | | <mi>y</mi> |
| | | <msqrt> |
| | | <mi>x</mi> |
| | | <mi>y</mi> |
| | | </msqrt> |
| | | <msup> |
| | | <mo stretchy="false">)</mo> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>⋅</mo> |
| | | <mroot> |
| | | <mrow> |
| | | <msup> |
| | | <mi>x</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mi>y</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mroot> |
| | | <mo>÷</mo> |
| | | <mroot> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | <msup> |
| | | <mi>y</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mroot> |
| | | </math>. |
| | | </p> |
| | | <examinations :cardList="questionData[128]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <h2 id="b023"> |
| | | 4.2 指数函数<span class="fontsz1">>>>>>>>></span> |
| | |
| | | <h3 id="c037"> |
| | | 4.2.1 指数函数的定义与图像<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 情境1:《庄子·天下篇》中有一段脍炙人口的话:“一尺之棰,日取其半,万世不竭.”这里的“一尺之棰”,即一尺(长度单位,1尺约合0.33 |
| | | m)长的木棍,“日取其半”即每天取它的一半.若一直“日取其半”,则每天剩下的木棍长度就是下面的一列数字. |
| | |
| | | <mo>.</mo> |
| | | </math> |
| | | <p class="right">①</p> |
| | | <p>其中指数<i>x</i>是自变量,定义域是<i>x</i>∈<b>N</b><sub>+</sub>.</p> |
| | | <p> |
| | | 其中指数<i>x</i>是自变量,定义域是<i>x</i>∈<b>N</b><sub>+</sub>. |
| | | </p> |
| | | <p> |
| | | 情境2:细胞每分裂1次其数量变为原来的两倍,则每次分裂后的细胞数量见表4-1. |
| | | </p> |
| | | <p class="img">表4-1</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0133-2.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0133-2.jpg" /> |
| | | </p> |
| | | <p> |
| | | 如果设细胞分裂的次数为<i>x</i>,对应分裂后的细胞数量为<i>y</i>,那么<i>y</i>与<i>x</i>的函数关系是 |
| | | </p> |
| | |
| | | <mo>.</mo> |
| | | </math> |
| | | <p class="right">②</p> |
| | | <p>其中指数<i>x</i>是自变量,定义域是<i>x</i>∈<b>N</b><sub>+</sub>.</p> |
| | | <p> |
| | | 其中指数<i>x</i>是自变量,定义域是<i>x</i>∈<b>N</b><sub>+</sub>. |
| | | </p> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"><img class="img-gn1" alt="" src="../../assets/images/gn.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/gn.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block">指数函数</p> |
| | | </div> |
| | |
| | | 的形式,其中指数<i>x</i>是自变量,底数<i>a</i>是一个大于0且不等于 |
| | | 1的常量. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 一般地,形如<i>y</i>=<i>a<sup>x</sup></i>(<i>a</i>>0,且<i>a</i>≠1)的函数叫作<b>指数函数</b>,其中指数<i>x</i>是自变量,定义域是<b>R</b>. |
| | | </p> |
| | |
| | | <!-- 123 --> |
| | | <div class="page-box" page="130"> |
| | | <div v-if="showPageList.indexOf(130) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | <img class="img-gn2" alt="" src="../../assets/images/hzjl.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block"> |
| | | 函数<i>y</i>=4.5<i><sup>x</sup></i>,<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </math>,<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </math>,<i>y</i>=1<i><sup>x</sup></i>中,哪些是指数函数呢?注意观察分析指数函数在形式表示上的特点. |
| | | </p> |
| | | <examinations :cardList="questionData[130]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | |
| | | </p> |
| | | <p>第一步:列表(如表4-2所示).</p> |
| | | <p class="img">表4-2</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0134-5.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0134-5.jpg" /> |
| | | </p> |
| | | <p> |
| | | 第二步:描点,并且用光滑的曲线连接所描的点,画出它们的图像(如图4-2所示). |
| | | </p> |
| | |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </math>, |
| | | <i>y</i>=2.3<i><sup>x</sup></i>,<i>y</i>=3<i><sup>x</sup></i>的图像,如图4-3所示. |
| | | </math>, <i>y</i>=2.3<i><sup>x</sup></i>,<i>y</i>=3<i><sup>x</sup></i>的图像,如图4-3所示. |
| | | <ul class="fl"> |
| | | <li style="margin-top: 30px;"> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0135-2.jpg" /></p> |
| | | <li style="margin-top: 30px"> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0135-2.jpg" /> |
| | | </p> |
| | | <p class="img">图4-2</p> |
| | | </li> |
| | | <li> |
| | | <p class="center"><img class="img-b" alt="" src="../../assets/images/0135-3.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-b" alt="" src="../../assets/images/0135-3.jpg" /> |
| | | </p> |
| | | <p class="img">图4-3</p> |
| | | </li> |
| | | </ul> |
| | | <h3 id="c038">4.2.2 指数函数的性质<span class="fontsz2">>>></span></h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /></p> |
| | | <h3 id="c038"> |
| | | 4.2.2 指数函数的性质<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 观察指数函数的图像,描述这些图像在位置、公共点和变化趋势等方面的共性特征. |
| | | </p> |
| | | <p>(1) 图中所有指数函数图像均在<i>x</i>轴的上方(<b>位置特征</b>);</p> |
| | | <p>(2) 图中所有指数函数图像都经过定点(0,1)(<b>公共点特征</b>);</p> |
| | | <p> |
| | | (1) 图中所有指数函数图像均在<i>x</i>轴的上方(<b>位置特征</b>); |
| | | </p> |
| | | <p> |
| | | (2) 图中所有指数函数图像都经过定点(0,1)(<b>公共点特征</b>); |
| | | </p> |
| | | <p> |
| | | (3) |
| | | 在定义域内,指数函数<i>y</i>=2<i><sup>x</sup></i>,<i>y</i>=2.3<i><sup>x</sup></i>,<i>y</i>=3<i><sup>x</sup></i>图像从左向右分别逐渐上升,在第二象限内向左与<i>x</i>轴无限接近;指数函数<math |
| | |
| | | <p> |
| | | 我们观察分析发现,指数函数<i>y</i>=<i>a<sup>x</sup></i>(<i>a</i>>0,且<i>a</i>≠1)的图像按底数<i>a</i>的取值,可分为0<<i>a</i><1和<i>a</i>>1两种类型. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 一般地,指数函数<i>y</i>=<i>a<sup>x</sup></i>(<i>a</i>>0,且<i>a</i>≠1)具有下列性质. |
| | | </p> |
| | |
| | | 指数函数<i>y</i>=<i>a<sup>x</sup></i>(<i>a</i>>0,且<i>a</i>≠1)的图像和性质可以总结如表4-3所示. |
| | | </p> |
| | | <p class="img">表4-3</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0136-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0136-1.jpg" /> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 判断下列函数哪些是指数函数,并画出函数图像验证. |
| | | </p> |
| | |
| | | <span class="zt-ls"><b>解</b></span> |
| | | 依据指数函数<i>y</i>=<i>a<sup>x</sup></i>的定义,<i>y</i>=0.5<i><sup>x</sup></i>是指数函数,<i>y</i>=2×3<i><sup>x</sup></i>和<i>y</i>=<i>x</i><sup>2</sup>不是指数函数.画出函数图像(如图4-4所示),函数<i>y</i>=0.5<i><sup>x</sup></i>的图像符合指数函数图像的特征;函数<i>y</i>=2×3<i><sup>x</sup></i>的图像虽与指数函数图像很相似,但并没有过定点(0,1);函数<i>y</i>=<i>x</i><sup>2</sup>的图像是二次函数的图像. |
| | | </p> |
| | | <p class="center"><img class="img-b" alt="" src="../../assets/images/0136-2.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-b" alt="" src="../../assets/images/0136-2.jpg" /> |
| | | </p> |
| | | <p class="img">图4-4</p> |
| | | <div class="bk-hzjl"> |
| | | <div class="bj1-hzjl"> |
| | |
| | | <img class="img-gn2" alt="" src="../../assets/images/hzjl.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block"> |
| | | 观察指数函数的图像,你还能发现其他共性特征吗?比如,指数函数<i>y</i>=2<i><sup>x</sup></i>和<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </math>的图像有什么关系?指数函数<i>y</i>=3<i><sup>x</sup></i>和<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </math>呢? |
| | | </p> |
| | | <examinations :cardList="questionData[131]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | </p> |
| | | <ul class="fl"> |
| | | <li> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0137-7.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0137-7.jpg" /> |
| | | </p> |
| | | <p class="img">图4-5</p> |
| | | </li> |
| | | <li> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0137-8.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0137-8.jpg" /> |
| | | </p> |
| | | <p class="img">图4-6</p> |
| | | </li> |
| | | <li> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0137-9.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0137-9.jpg" /> |
| | | </p> |
| | | <p class="img">图4-7</p> |
| | | </li> |
| | | </ul> |
| | |
| | | <!-- 127 --> |
| | | <div class="page-box" page="134"> |
| | | <div v-if="showPageList.indexOf(134) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | 函数<i>y</i>=3<i><sup>x</sup></i>在定义域内是增函数. |
| | | </p> |
| | | <p>因此,<i>m</i>≥2,即<i>m</i>的取值范围为[2,+∞).</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p>1.指出下列函数中的指数函数,并分别指出其底数、指数.</p> |
| | | <p> |
| | | (1) <i>y</i>=0.5<i><sup>x</sup></i>;(2) <i>y</i>=3×4<i><sup>x</sup></i>;(3) |
| | | <i>y</i>=2<i><sup>-x</sup></i>. |
| | | </p> |
| | | <p> |
| | | 2.已知函数<i>f</i>(<i>x</i>)=3<i><sup>x</sup></i>,求<i>f</i>(0),<i>f</i>(2),<i>f</i>(-2),<math display="0"> |
| | | <mi>f</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>的值. |
| | | </p> |
| | | <p>3.判断下列函数在(-∞,+∞)内的单调性.</p> |
| | | <p> |
| | | (1) <i>y</i>=0.9<i><sup>x</sup></i>;(2) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </math>;(3) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mn>3</mn> |
| | | <mfrac> |
| | | <mi>x</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p>4.比较下列各题中两个值的大小.</p> |
| | | <p> |
| | | (1) 1.2<sup>0.3</sup>与1.2<sup>0.5</sup>;(2) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>2.1</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>与<math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>2.2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>与1;(4) 1与<math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>0.21</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>. |
| | | </p> |
| | | <p>5.求下列函数的定义域.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mrow> |
| | | <msup> |
| | | <mn>2</mn> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <msup> |
| | | <mn>3</mn> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | <mo>−</mo> |
| | | <mn>81</mn> |
| | | </msqrt> |
| | | </math>;(3) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <msqrt> |
| | | <mn>1</mn> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 6.已知函数<i>f</i>(<i>x</i>)=<i>a<sup>x</sup></i>(<i>a</i>>0,且<i>a</i>≠1)的图像过点(3,64). |
| | | </p> |
| | | <p>(1) 求函数的解析式;</p> |
| | | <p> |
| | | (2) 求<math display="0"> |
| | | <mi>f</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>的值. |
| | | </p> |
| | | <examinations :cardList="questionData[134]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 128 --> |
| | | <div class="page-box" page="135"> |
| | | <div v-if="showPageList.indexOf(135) > -1"> |
| | |
| | | <div class="padding-116"> |
| | | <h3 id="c039">习题4.2<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p>1.选择题.</p> |
| | | <p>(1) 下列函数中,在区间(0,+∞)上是增函数的是( ).</p> |
| | | <p>A.<i>y</i>=<i>x</i><sup>-3</sup></p> |
| | | <p> |
| | | B.<i>y</i>=3<i><sup>-x</sup></i> |
| | | </p> |
| | | <p> |
| | | C.<i>y</i>=0.4<i><sup>x</sup></i> |
| | | </p> |
| | | <p>D.<i>y</i>=<i>x</i><sup>0.2</sup></p> |
| | | <p> |
| | | (2) 已知<math display="0"> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo><</mo> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | </mrow> |
| | | </msup> |
| | | </math>,则<i>a</i>的取值范围是( ). |
| | | </p> |
| | | <p>A.(0,1)</p> |
| | | <p>B.(-∞,0)</p> |
| | | <p>C.(1,+∞) D(0,+∞)</p> |
| | | <p> |
| | | (3) 函数<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </math>,当<i>x</i>∈(0,+∞)时,<i>y</i>∈( ) . |
| | | </p> |
| | | <p><i>A</i>.(1,+∞)<i>B</i>.(0,+∞)</p> |
| | | <p><i>C</i>.(0,1) <i>D</i>.(-∞,0)∪(0,+∞)</p> |
| | | <p>2.比较下列各题中两个值的大小.</p> |
| | | <p> |
| | | (1) 3.2<sup>3</sup>与 3.2<sup>2</sup>;(2) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mrow> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | </mrow> |
| | | </msup> |
| | | </math>与 |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>3.14</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3) 3<sup>-2</sup> 与<math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>;(4) 1 与0.32<sup>-2.1</sup>. |
| | | </p> |
| | | <p>3.求下列函数的定义域.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>x</mi> |
| | | <mrow> |
| | | <msup> |
| | | <mn>5</mn> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>9</mn> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>3</mn> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | </math>;(3) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>1</mn> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 4.指数函数<i>y</i>=(<i>a</i>-1)<i><sup>x</sup></i>在<b>R</b>上单调递减,求<i>a</i>的取值范围. |
| | | </p> |
| | | <p>5.求下列函数的解析式.</p> |
| | | <p> |
| | | (1) 点(3,<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mn>3</mn> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>27</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>)在指数函数<i>g</i>(<i>x</i>)的图像上; |
| | | </p> |
| | | <p>(2) 点(4,16)在指数函数<i>f</i>(<i>x</i>)的图像上.</p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p>1.求下列不等式中<i>x</i>的取值范围.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <msup> |
| | | <mn>2</mn> |
| | | <mrow> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo><</mo> |
| | | <msup> |
| | | <mn>2</mn> |
| | | <mrow> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>x</mi> |
| | | <mo>+</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | <mo>></mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>x</mi> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>. |
| | | </p> |
| | | <examinations :cardList="questionData[135]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 129 --> |
| | | <div class="page-box" page="136"> |
| | | <div v-if="showPageList.indexOf(136) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | <p><span>129</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | <p> |
| | | 2.已知函数<i>f</i>(<i>x</i>)=<i>a<sup>x</sup></i>(<i>a</i>>0)的图像经过点(2,<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mn>2</mn> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>). |
| | | </p> |
| | | <p>(1) 求<i>a</i>的值;</p> |
| | | <p> |
| | | (2) 若<math display="0"> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo><</mo> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <msup> |
| | | <mi>x</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </mrow> |
| | | </msup> |
| | | </math>,求<i>x</i>的取值范围. |
| | | </p> |
| | | <p> |
| | | 3.已知函数<i>f</i>(<i>x</i>)=2<i><sup>|x|</sup></i>. |
| | | </p> |
| | | <p> |
| | | (1) 画出它的图像;(2) 由图像指出<i>f</i>(<i>x</i>)的单调区间; |
| | | </p> |
| | | <p> |
| | | (3) 求<i>f</i>(<i>x</i>)的最值;(4) |
| | | 判断<i>f</i>(<i>x</i>)的奇偶性. |
| | | </p> |
| | | <p>(提示:分<i>x</i>≥0和<i>x</i><0两种情况分析)</p> |
| | | </div> |
| | | <h2 id="b024">4.3 对数<span class="fontsz1">>>>>>>>></span></h2> |
| | | <h2 id="b024"> |
| | | 4.3 对数<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <h3 id="c040">4.3.1 对数的定义<span class="fontsz2">>>></span></h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p> |
| | | 在上一节“观察思考”的情境1中,我们提到了《庄子·天下篇》中的“一尺之棰,日取其半,万世不竭”.现已知“一尺之棰”剩下八分之一尺,请问过去了几天?如果是剩下<i>N</i>尺呢? |
| | | </p> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"><img class="img-gn1" alt="" src="../../assets/images/gn.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/gn.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block">对数</p> |
| | | <p class="block">底数</p> |
| | |
| | | <p class="block">常用对数</p> |
| | | <p class="block">自然对数</p> |
| | | </div> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 一般地,如果<i>a<sup>x</sup></i>=<i>N</i>(<i>a</i>>0,且<i>a</i>≠1),那么数<i>x</i>叫作以<i>a</i>为底<i>N</i>的<b>对数</b>,记作 |
| | | </p> |
| | |
| | | 式子<i>a<sup>b</sup></i>=<i>N</i>叫作<b>指数式</b>,log |
| | | <i><sub>a</sub>N</i>=<i>b</i>叫作<b>对数式</b>.它们的关系如下. |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0140-3.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0140-3.jpg" /> |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 130 --> |
| | | <div class="page-box" page="137"> |
| | | <div v-if="showPageList.indexOf(137) > -1"> |
| | |
| | | </p> |
| | | <p> |
| | | 另外,在科技、经济以及社会生活中经常使用无理数e,它的值为2.718 |
| | | 28…,以e为底的对数叫作<b>自然对数</b>.<i>N</i>的自然对数log <sub>e</sub><i>N</i>简记作ln<i>N</i>.例如,log<sub>e</sub>8简记作ln8. |
| | | 28…,以e为底的对数叫作<b>自然对数</b>.<i>N</i>的自然对数log |
| | | <sub>e</sub><i>N</i>简记作ln<i>N</i>.例如,log<sub>e</sub>8简记作ln8. |
| | | </p> |
| | | <p>根据对数的定义,对数有以下性质.</p> |
| | | <p>(1) 零和负数没有对数;</p> |
| | |
| | | <img class="img-gn2" alt="" src="../../assets/images/hzjl.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block">请同学们分小组合作推导对数的性质,并进行交流分享.</p> |
| | | <examinations :cardList="questionData[137]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 把下列指数式写成对数式. |
| | |
| | | <span class="zt-ls"><b>例5</b></span> 求下列各式的值. |
| | | </p> |
| | | <p> |
| | | (1) log<sub>5</sub>1;(2) log<sub>7</sub>7;(3) lg 10;(4) ln e. |
| | | (1) log<sub>5</sub>1;(2) log<sub>7</sub>7;(3) lg 10;(4) |
| | | ln e. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls2"><b>分析</b></span> 利用性质“1的对数为0”和“底数的对数为1” 直接得答案,不必转化成指 |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 131 --> |
| | | <div class="page-box" page="138"> |
| | | <div v-if="showPageList.indexOf(138) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | <span class="zt-ls"><b>解</b></span>(1) log<sub>5</sub>1=0;(2) log<sub>7</sub>7=1; |
| | | </p> |
| | | <p>(3) lg10=log<sub>10</sub>10=1;(4) ln e=log<sub>e</sub>e=1.</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p>1.把下列指数式写成对数式.</p> |
| | | <p> |
| | | (1) 3<sup>6</sup>=729;(2) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mn>8</mn> |
| | | </math>;(3) |
| | | <math display="0"> |
| | | <msup> |
| | | <mn>25</mn> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mn>5</mn> |
| | | </math>;(4) 10<sup>3</sup>=1 000. |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <p>2.把下列对数式写成指数式.</p> |
| | | <p> |
| | | (1) log <sub>4</sub>64=3;(2) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msub> |
| | | <mn>8</mn> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | </math>;(3) lg0.1=-1;(4) |
| | | <math display="0"> |
| | | <mi>ln</mi> |
| | | <msqrt> |
| | | <mi>e</mi> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>. |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[138]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <h3 id="c041"> |
| | | 4.3.2 对数的运算性质<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /> |
| | | </p> |
| | | <p>3.求下列各式中<i>N</i>的值.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>27</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mi mathvariant="bold">N</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>;(2) ln<i>N</i>=0;(3) lg<i>N</i>=1. |
| | | </p> |
| | | <p>4.求下列各式的值.</p> |
| | | <p> |
| | | (1) log <sub>6</sub>36;(2) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>;(3) lg100;(4) log <sub>3</sub>3<sup>2</sup>; |
| | | </p> |
| | | <p> |
| | | (5) log <sub>11</sub>11;(6) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msub> |
| | | <mn>1</mn> |
| | | </math>;(7) lg 10+ln e. |
| | | </p> |
| | | <h3 id="c041">4.3.2 对数的运算性质<span class="fontsz2">>>></span></h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /></p> |
| | | <p> |
| | | 利用对数式与指数式的关系,填写表4-4,猜想对数的运算性质,并与同学交流. |
| | | </p> |
| | | <p class="img">表4-4</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0142-8.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0142-8.jpg" /> |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 132 --> |
| | | <div class="page-box" page="139"> |
| | | <div v-if="showPageList.indexOf(139) > -1"> |
| | | |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>132</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p>我们可以得到两个正数的积、商、幂的对数运算性质.</p> |
| | | <p> |
| | | (1) |
| | |
| | | <mtext>. </mtext> |
| | | </math> |
| | | <p> |
| | | (3) 幂的对数:<b>一个正数幂的对数,等于幂指数乘这个数的对数,</b>即 |
| | | (3) |
| | | 幂的对数:<b>一个正数幂的对数,等于幂指数乘这个数的对数,</b>即 |
| | | </p> |
| | | <p class="center"> |
| | | log<i><sub>a</sub>M<sup>q</sup></i>=<i>q</i>log |
| | |
| | | <img class="img-gn2" alt="" src="../../assets/images/hzjl.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block">请尝试证明性质(2) 和(3) ,并与同学交流分享.</p> |
| | | <examinations :cardList="questionData[139]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <p> |
| | | <span |
| | |
| | | <!-- 133 --> |
| | | <div class="page-box" page="140"> |
| | | <div v-if="showPageList.indexOf(140) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p>1.填空题.</p> |
| | | <p>lg 1000=____,ln e<sup>2</sup>=____, lg 0.1=____,</p> |
| | | <p> |
| | | log<sub>2</sub>4=____,log<sub>3</sub>9=____, |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | </math>____, |
| | | </p> |
| | | <p> |
| | | log<sub>3</sub>81=____,log<sub>2</sub>4-log<sub>2</sub>8=___,lg 2+lg |
| | | 5=___. |
| | | </p> |
| | | <p> |
| | | 2.用lg <i>x</i>,lg <i>y</i>,lg |
| | | <i>z</i>表示下列各式(式中字母均为正实数). |
| | | </p> |
| | | <p> |
| | | (1) lg(<i>x</i><sup>2</sup><i>yz</i><sup>3</sup>);(2) |
| | | <math display="0"> |
| | | <mi>log</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>x</mi> |
| | | <msup> |
| | | <mi>y</mi> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <msup> |
| | | <mi>z</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>;(3) |
| | | <math display="0"> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <msup> |
| | | <mi>x</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mrow> |
| | | <msup> |
| | | <mi>y</mi> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <msqrt> |
| | | <mi>z</mi> |
| | | </msqrt> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p>3.计算.</p> |
| | | <p> |
| | | (1) log<sub>3</sub>(27×9<sup>2</sup>);(2) |
| | | <math display="0"> |
| | | <mi>ln</mi> |
| | | <msqrt> |
| | | <mi>e</mi> |
| | | </msqrt> |
| | | </math>;(3) |
| | | <math display="0"> |
| | | <mi>lg</mi> |
| | | <msqrt> |
| | | <mn>0.001</mn> |
| | | </msqrt> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (4) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>7</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mroot> |
| | | <mn>49</mn> |
| | | <mn>3</mn> |
| | | </mroot> |
| | | </math>;(5) log<sub>3</sub>36-log<sub>3</sub>4;(6) lg 5+lg 20; |
| | | </p> |
| | | <p> |
| | | (7) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>;(8) log <sub>0.5</sub>1-log <sub>0.5</sub>4. |
| | | </p> |
| | | <examinations :cardList="questionData[140]" :hideCollect="true" sourceType="json" inputBc="#d3edfa" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <h3 id="c042"> |
| | | 4.3.3(选学)换底公式、对数恒等式<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 设log<i><sub>a</sub>N</i>=<i>x</i>,则<i>a<sup>x</sup></i>=<i>N</i>,两边取以<i>c</i>为底的对数,得log<i><sub>c</sub>a<sup>x</sup></i>=log<i><sub>c</sub>N</i>,于是<i>x</i>log<i><sub>c</sub>a</i>=log<i><sub>c</sub>N</i>,即<math |
| | | display="0"> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 134 --> |
| | | <div class="page-box" page="141"> |
| | | <div v-if="showPageList.indexOf(141) > -1"> |
| | |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p>1.求下列各式的值.</p> |
| | | <p> |
| | | (1) log <sub>25</sub>49·log<sub>7</sub>125;(2) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo>⋅</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo>⋅</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>49</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 2.证明:log<i><sub>a</sub>b</i>·log<i><sub>b</sub>a</i>=1(<i>a</i>>0,<i>b</i>>0,且<i>a</i>≠1,<i>b</i>≠1). |
| | | </p> |
| | | <p> |
| | | 3.已知log<sub>2</sub>3=<i>a</i>,log<sub>2</sub>5=<i>b</i>,求log<sub>4</sub>15的值. |
| | | </p> |
| | | <p>4.求下列各式的值.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <msup> |
| | | <mn>3</mn> |
| | | <mrow> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mn>11</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <msup> |
| | | <mn>25</mn> |
| | | <mrow> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>;(3) |
| | | <math display="0"> |
| | | <msup> |
| | | <mn>7</mn> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mo>+</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>7</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>. |
| | | </p> |
| | | <examinations :cardList="questionData[141]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 135 --> |
| | | <div class="page-box" page="142"> |
| | | <div v-if="showPageList.indexOf(142) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | <div class="padding-116"> |
| | | <h3 id="c043">习题4.3<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p>1.选择题.</p> |
| | | <p> |
| | | (1) 指数式4<i><sup>x</sup></i>=5写成对数式为( ). |
| | | </p> |
| | | <p>A.log <sub>4</sub><i>x</i>=5</p> |
| | | <p>B.log<sub>4</sub>5=<i>x</i></p> |
| | | <p>C.log <sub>5</sub><i>x</i>=4</p> |
| | | <p>D.log<sub>5</sub>4=<i>x</i></p> |
| | | <p>(2) 对数式lg <i>x</i>=3写成指数式为( ).</p> |
| | | <p> |
| | | A.10<i><sup>x</sup></i>=3 |
| | | </p> |
| | | <p>B.10<sup>3</sup>=<i>x</i></p> |
| | | <p>C.<i>x</i><sup>3</sup>=10</p> |
| | | <p> |
| | | D.3<i><sup>x</sup></i>=10 |
| | | </p> |
| | | <p>2.计算.</p> |
| | | <p> |
| | | (1) log <sub>5</sub>5<sup>4</sup>;(2) lg 0.001;(3) |
| | | 10<sup>lg2</sup>; |
| | | </p> |
| | | <p> |
| | | (4) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>7</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mn>2</mn> |
| | | <mo>+</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>7</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>;(5) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mn>15</mn> |
| | | <mo>+</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>;(6) |
| | | <math display="0"> |
| | | <mi>lg</mi> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mi>lg</mi> |
| | | <mn>125</mn> |
| | | </math>. |
| | | </p> |
| | | <p>3.化简lg 2 100-lg 21=( ).</p> |
| | | <p>A.1</p> |
| | | <p>B.2</p> |
| | | <p>C.-1</p> |
| | | <p>D.-2</p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p>计算.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msub> |
| | | <msqrt> |
| | | <mn>8</mn> |
| | | </msqrt> |
| | | </math>;(2) 10<sup>1+lg3</sup>; |
| | | </p> |
| | | <p> |
| | | (3) log<sub>4</sub>64;(4) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msub> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mo>·</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>9</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mn>8</mn> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (5) |
| | | <math display="0"> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>5</mn> |
| | | <mo>+</mo> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>25</mn> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>8</mn> |
| | | <mo>+</mo> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>2</mn> |
| | | </math>;(6) log<sub>6</sub>20-log <sub>6</sub>5+2log<sub>6</sub>3. |
| | | </p> |
| | | <examinations :cardList="questionData[142]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <h2 id="b025"> |
| | | 4.4 对数函数<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <h3 id="c044">4.4.1 对数函数的定义<span class="fontsz2">>>></span></h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <h3 id="c044"> |
| | | 4.4.1 对数函数的定义<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p> |
| | | 在第二节“观察思考”的情境2中,细胞由1个分裂为2个,2个分裂为4个……如果已知分裂<i>x</i>次后对应细胞数量是1 |
| | | 024个,那么如何求分裂的次数<i>x</i>呢? |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 136 --> |
| | | <div class="page-box" page="143"> |
| | | <div v-if="showPageList.indexOf(143) > -1"> |
| | |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 设1个细胞经过<i>y</i>次分裂后得到<i>x</i>个细胞,则<i>x</i>与<i>y</i>的函数关系式为<i>x</i>=2<i><sup>y</sup></i>,将此指数式写为对数式,得到 |
| | | </p> |
| | |
| | | <p>这个式子就是用分裂后的细胞数量<i>x</i>来表示分裂的次数<i>y</i>.</p> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"><img class="img-gn1" alt="" src="../../assets/images/gn.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/gn.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block">对数函数</p> |
| | | </div> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 通过指数与对数的关系我们观察到:<i>y</i>=log<sub>2</sub><i>x</i>是一个函数,其自变量<i>x</i>位于真数位置,底数是常数.类比指数函数定义的学习过程,我们可以用字母<i>a</i>代替底数2,即有<i>y</i>=log<sub>a</sub><i>x</i>(<i>a</i>>0,且<i>a</i>≠1)这类特征的函数. |
| | | </p> |
| | |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 要使函数有意义,必须满足<i>x</i>-3>0,解得<i>x</i>>3. |
| | | </p> |
| | | <p>所以,<i>y</i>=log <sub>0.5</sub>(<i>x</i>-3)的定义域是(3,+∞).</p> |
| | | <p> |
| | | 所以,<i>y</i>=log <sub>0.5</sub>(<i>x</i>-3)的定义域是(3,+∞). |
| | | </p> |
| | | <p> |
| | | (2) 要使函数有意义,必须满足4-<i>x</i><sup>2</sup>>0,解得 |
| | | -2<<i>x</i><2. |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 137 --> |
| | | <div class="page-box" page="144"> |
| | | <div v-if="showPageList.indexOf(144) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p>1.填空题.</p> |
| | | <p> |
| | | (1) 函数<i>y</i>=log<sub>5</sub><i>x</i>的底数为____,定义域为____; |
| | | </p> |
| | | <p> |
| | | (2) 函数<math display="0"> |
| | | <mi>f</mi> |
| | | <mo stretchy="false">(</mo> |
| | | <mi>x</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>=</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </math>,则<i>f</i>(1)=____,<i>f</i>(5)=____, <i>f</i>(25)= ____; |
| | | </p> |
| | | <p> |
| | | (3) 已知<i>f</i>(<i>x</i>)=log<sub>2</sub><i>x</i>,且<i>f</i>(<i>a</i>)=-3,则<i>a</i>=____. |
| | | </p> |
| | | <p>2.已知<i>f</i>(<i>x</i>)=lg <i>x</i>.</p> |
| | | <p> |
| | | (1) 求<i>f</i>(0.1)的值;(2) |
| | | 若<i>f</i>(<i>a</i>)=-2,求<i>a</i>的值. |
| | | </p> |
| | | <p>3.求下列函数的定义域.</p> |
| | | <p> |
| | | (1)<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>5</mn> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>x</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </math>;(2) <i>y</i>=log<sub>2</sub>(9-<i>x</i><sup>2</sup>). |
| | | </p> |
| | | <examinations :cardList="questionData[144]" :hideCollect="true" sourceType="json" inputBc="#d3edfa" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <h3 id="c045"> |
| | | 4.4.2 对数函数的图像与性质<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 与研究指数函数的图像和性质一样,我们首先通过描点法画出对数函数的图像,然后归纳总结函数的相关性质.下面我们以<i>y</i>=log<sub>2</sub><i>x</i>和<math display="0"> |
| | | <mi>y</mi> |
| | |
| | | </p> |
| | | <p>第一步:计算部分数值并列表(如表4-5所示).</p> |
| | | <p class="img">表4-5</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0148-3.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0148-3.jpg" /> |
| | | </p> |
| | | <p> |
| | | 第二步:描点,并用光滑的曲线连接所描的点,画出它们的图像,如图4-8所示. |
| | | </p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 138 --> |
| | | <div class="page-box" page="145"> |
| | | <div v-if="showPageList.indexOf(145) > -1"> |
| | | |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>138</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0149-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-b" alt="" src="../../assets/images/0149-1.jpg" /> |
| | | </p> |
| | | <p class="img">图4-8</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0149-2.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0149-2.jpg" /> |
| | | </p> |
| | | <p class="img">图4-9</p> |
| | | <p><b>类比归纳</b></p> |
| | | <p> |
| | | 类比指数函数图像特征的观察方法,观察对数函数的图像,描述它们的图像在位置、公共点和变化趋势等方面的共性特征. |
| | | </p> |
| | | <p> |
| | | (1) 图中所有对数函数的图像均在<i>y</i>轴的右侧(<b>位置特征</b>); |
| | | (1) |
| | | 图中所有对数函数的图像均在<i>y</i>轴的右侧(<b>位置特征</b>); |
| | | </p> |
| | | <p> |
| | | (2) 图中所有对数函数的图像都经过定点(1,0)(<b>公共点特征</b>); |
| | | (2) |
| | | 图中所有对数函数的图像都经过定点(1,0)(<b>公共点特征</b>); |
| | | </p> |
| | | <p> |
| | | (3) 在定义域内,对数函数<math display="0"> |
| | |
| | | <p> |
| | | 类比指数函数的图像,对数函数<i>y</i>=log<i><sub>a</sub>x</i>(<i>a</i>>0,且<i>a</i>≠1)的图像按底数<i>a</i>的取值,可分为0<<i>a</i><1和<i>a</i>>1两种类型,我们从指数式与对数式的关系也可发现. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 一般地,对数函数<i>y</i>=log<i><sub>a</sub>x</i>(<i>a</i>>0,且<i>a</i>≠1)具有下列性质. |
| | | </p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 139 --> |
| | | <div class="page-box" page="146"> |
| | | <div v-if="showPageList.indexOf(146) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="img">表4-6</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0150-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0150-1.jpg" /> |
| | | </p> |
| | | <div class="bk-hzjl"> |
| | | <div class="bj1-hzjl"> |
| | | <p class="left"> |
| | | <img class="img-gn2" alt="" src="../../assets/images/hzjl.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block"> |
| | | 1.你还能从图4-10中观察发现其他共性特征吗?比如,对数函数<i>y</i>=log |
| | | 2<i>x</i>和<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </math>的图像有什么关系? |
| | | </p> |
| | | <p class="block"> |
| | | 2.两人一组,一人用表格呈现指数函数的图像与性质,另一人用表格呈现对数函数的图像与性质,然后对比两个函数的图像与性质,归纳总结为一个表格,并与同学交流分享. |
| | | </p> |
| | | <examinations :cardList="questionData[146]" :hideCollect="true" sourceType="json" |
| | | v-if="questionData" ></examinations> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 比较下列各组数中两个值的大小. |
| | |
| | | <sub>0.2</sub>7与log <sub>0.2</sub>9; |
| | | </p> |
| | | <p> |
| | | (3) log<sub>5</sub>4与1;(4)log<sub>3</sub>4与log <sub>0.3</sub>4. |
| | | (3) log<sub>5</sub>4与1;(4)log<sub>3</sub>4与log |
| | | <sub>0.3</sub>4. |
| | | </p> |
| | | <p class="block"> |
| | | <span class="zt-ls2"><b>分析</b></span> 若两个对数的底数相同,可利用对数函数的单调性直接比较;若底数不同,可采用先与中间量(通常是0或1)进行比较,再利用不等式传递性得出结论. |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 140 --> |
| | | <div class="page-box" page="147"> |
| | | <div v-if="showPageList.indexOf(147) > -1"> |
| | |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p>(3) log<sub>5</sub>4<log<sub>5</sub>5=1,即log<sub>5</sub>4<1.</p> |
| | | <p> |
| | | (3) log<sub>5</sub>4<log<sub>5</sub>5=1,即log<sub>5</sub>4<1. |
| | | </p> |
| | | <ul class="fl"> |
| | | <li> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0151-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0151-1.jpg" /> |
| | | </p> |
| | | <p class="img">图4-10</p> |
| | | </li> |
| | | <li> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0151-2.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0151-2.jpg" /> |
| | | </p> |
| | | <p class="img">图4-11</p> |
| | | </li> |
| | | </ul> |
| | |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为<i>y</i>=log 4<i>x</i>在(0,+∞)上是增函数,所以<i>x</i><5. |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为<i>y</i>=log |
| | | 4<i>x</i>在(0,+∞)上是增函数,所以<i>x</i><5. |
| | | </p> |
| | | <p>又因为<i>x</i>>0,所以0<<i>x</i><5.</p> |
| | | <p>所以不等式的解集为(0,5).</p> |
| | |
| | | </mrow> |
| | | </math>). |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p> |
| | | 1.求函数<i>y</i>=log <sub>0.7</sub>(2<i>x</i>-<i>x</i><sup>2</sup>)的定义域. |
| | | </p> |
| | | <p>2.比较下列各组数中两个值的大小.</p> |
| | | <p> |
| | | (1) <i>lg</i>6 与<i>lg</i>8;(2) log <sub>0.3</sub>5 与log |
| | | <sub>0.3</sub>7; |
| | | </p> |
| | | <p> |
| | | (3)log <sub>0.3</sub>5与0;(4) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msub> |
| | | <mrow> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | </math>与<math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | </math>. |
| | | </p> |
| | | <p>3.解下列不等式.</p> |
| | | <p> |
| | | (1) log <sub>3</sub><i>x</i>>log 34;(2)<math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo><</mo> |
| | | <mn>1</mn> |
| | | </math>. |
| | | </p> |
| | | <examinations :cardList="questionData[147]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 141 --> |
| | | <div class="page-box" page="148"> |
| | | <div v-if="showPageList.indexOf(148) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>141</span></p> |
| | | <p><span>141-142</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <h3 id="c046">习题4.4<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p>1.选择题.</p> |
| | | <p> |
| | | (1) 函数<i>y</i>=log<i><sub>a</sub>x</i>(<i>a</i>>0,且<i>a</i>≠1)的图像过定点( ). |
| | | </p> |
| | | <p>A.(0,0)</p> |
| | | <p>B.(0,1)</p> |
| | | <p>C.(1,0)</p> |
| | | <p>D.(1,1)</p> |
| | | <p> |
| | | (2) 函数<i>f</i>(<i>x</i>)=log<i><sub>a</sub>x</i>(0<<i>a</i><1)中, |
| | | <i>f</i>(3)和<i>f</i>(5)的大小关系是( ). |
| | | </p> |
| | | <p>A.<i>f</i>(3)><i>f</i>(5)</p> |
| | | <p>B.<i>f</i>(3)=<i>f</i>(5)</p> |
| | | <p>C.<i>f</i>(3)<<i>f</i>(5)</p> |
| | | <p>D.不能比较</p> |
| | | <p>(3) 函数<i>y</i>=lg(<i>x</i>+1)的定义域为( ).</p> |
| | | <p>A.(-∞,+∞)</p> |
| | | <p>B.(-1,+∞)</p> |
| | | <p>C.(0,+∞)</p> |
| | | <p>D.(1,+∞)</p> |
| | | <p> |
| | | (4) 关于函数<i>y</i>=log<sub>3</sub><i>x</i>和函数<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </math>图像的对称性,正确的是( ). |
| | | </p> |
| | | <p>A.关于<i>x</i>轴对称</p> |
| | | <p>B.关于<i>y</i>轴对称</p> |
| | | <p>C.关于原点对称</p> |
| | | <p>D.无对称性</p> |
| | | <p>2.比较下列各组数中两个值的大小.</p> |
| | | <p> |
| | | (1) lg 6.2 与lg 2<i>π</i>;(2) log <sub>0.5</sub>6与log |
| | | <sub>0.5</sub>4; |
| | | </p> |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>0.5</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>与1;(4) |
| | | <math display="0"> |
| | | <mi>ln</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>与0. |
| | | </p> |
| | | <p> |
| | | 3.求函数<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>2</mn> |
| | | <mo>−</mo> |
| | | <mi>x</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | <mo>+</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>的定义域. |
| | | </p> |
| | | <p>4.求下列函数的定义域.</p> |
| | | <p> |
| | | (1)<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mrow> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>1</mn> |
| | | <mo>−</mo> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </msqrt> |
| | | </math>;(3) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <msqrt> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>0.5</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </msqrt> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p>1.选择题.</p> |
| | | <p> |
| | | (1) 对数函数<i>y</i>=log<i><sub>a</sub>x</i>(<i>a</i>>0,且<i>a</i>≠1)的图像过点(4,2),则<i>a</i>=( ). |
| | | </p> |
| | | <p>A.±2</p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p>C.2</p> |
| | | <p>D.4</p> |
| | | <p> |
| | | (2) 函数<i>y</i>=log <sub>(a-1)</sub><i>x</i>在区间(0,+∞)上是减函数,则<i>a</i>的取值范围是( ). |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 142 --> |
| | | <div class="page-box" page="149"> |
| | | <div v-if="showPageList.indexOf(149) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>142</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | <p>A.(0,1)</p> |
| | | <p>B.(1,2)</p> |
| | | <p>C.(1,+∞)</p> |
| | | <p>D.(0,2)</p> |
| | | <p> |
| | | (3) 函数<i>y</i>=3+log<i><sub>a</sub>x</i>(<i>a</i>>0,且<i>a</i>≠1)的图像过定点( ). |
| | | </p> |
| | | <p>A.(0,1)</p> |
| | | <p>B.(1,0)</p> |
| | | <p>C.(1,3)</p> |
| | | <p>D.(1,4)</p> |
| | | <p> |
| | | (4) 已知log<sub>0.5</sub><i>x</i>>log<sub>0.5</sub>3,则<i>x</i>的取值范围是( ). |
| | | </p> |
| | | <p>A.(3,+∞)</p> |
| | | <p>B.(0,+∞)</p> |
| | | <p>C.(-∞,3)</p> |
| | | <p>D.(0,3)</p> |
| | | <p> |
| | | (5) |
| | | 已知<i>a</i>=log<sub>0.7</sub>0.8,<i>b</i>=log<sub>0.7</sub>1.9,<i>c</i>=log<sub>5</sub>1,则<i>a</i>,<i>b</i>,<i>c</i>的大小关系是( ). |
| | | </p> |
| | | <p>A.<i>a</i><<i>b</i><<i>c</i></p> |
| | | <p>B.<i>a</i><<i>c</i><<i>b</i></p> |
| | | <p>C.<i>b</i><<i>a</i><<i>c</i></p> |
| | | <p>D.<i>b</i><<i>c</i><<i>a</i></p> |
| | | <p>2.求下列函数的定义域.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>x</mi> |
| | | <msqrt> |
| | | <mn>1</mn> |
| | | <mo>−</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </msqrt> |
| | | </mfrac> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </msqrt> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 3.已知函数<i>f</i>(<i>x</i>)=log<i><sub>a</sub>x</i>(<i>a</i>>0,且<i>a</i>≠1)的图像过点(9,-2),求<i>f</i>(3)的值. |
| | | </p> |
| | | <p> |
| | | 4.我国经济总量占世界经济的比重达18.5%,居世界第二位.2020年我国全年<i>GDP</i>为1 |
| | | 015 |
| | | 986亿元,取得了超过100万亿的历史性成就.2021年我国<i>GDP</i>预期目标是增长率超过6.0%.假设我国每年<i>GDP</i>的增长率均为6.0%,从2021年开始,大约经过多少年,我国能实现全年<i>GDP</i>比2021年翻一番? |
| | | </p> |
| | | <examinations :cardList="questionData[148]" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <h2 id="b026"> |
| | | 4.5 指数函数与对数函数的实际应用<span class="fontsz1">>>>>>>>></span> |
| | |
| | | 178万人,其中城镇常住人口90 |
| | | 199万人,占总人口的比例(常住人口城镇化率)为63.89%,与2010年相比,提高了14.21个百分点. |
| | | </p> |
| | | <p>(1) 假设此后每年都增加700万人口,20年后我国大陆人口总数是多少?</p> |
| | | <p> |
| | | (1) 假设此后每年都增加700万人口,20年后我国大陆人口总数是多少? |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 142 --> |
| | | <div class="page-box hidePage" page="149"> |
| | | </div> |
| | | <!-- 143 --> |
| | | <div class="page-box" page="150"> |
| | | <div v-if="showPageList.indexOf(150) > -1"> |
| | |
| | | <p class="block">2020年年末 人口约为141 178万;</p> |
| | | <p class="block">经过1年 人口约为141 178(1+1%)万;</p> |
| | | <p class="block"> |
| | | 经过2年 人口约为141 178(1+1%)(1+1%)=141 178(1+1%)<sup>2</sup>万; |
| | | 经过2年 人口约为141 178(1+1%)(1+1%)=141 |
| | | 178(1+1%)<sup>2</sup>万; |
| | | </p> |
| | | <p class="block"> |
| | | 经过3年 人口约为141 178(1+1%)<sup>2</sup>(1+1%)=141 |
| | |
| | | 178万;假设每年人口的平均增长率是1%,经过20年后我国大陆人口约为172 |
| | | 263.99万. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 比较两种增长方式,随着时间推移,“指数增长”方式更具有爆发性.探究两种增长方式的特点,并分别列举社会生活中的“线性增长”和“指数增长”现象. |
| | | </p> |
| | |
| | | <i>x</i><sub>1</sub>=1.013×10<sup>5</sup>,<i>y</i><sub>1</sub>=0, |
| | | </p> |
| | | <p class="center"> |
| | | <i>x</i><sub>2</sub>=4.21×10<sup>4</sup>,<i>y</i><sub>2</sub>=7 028, |
| | | <i>x</i><sub>2</sub>=4.21×10<sup>4</sup>,<i>y</i><sub>2</sub>=7 |
| | | 028, |
| | | </p> |
| | | <p>分别代入函数关系式 <i>y</i>=<i>k</i> ln <i>x</i>+<i>c</i>,</p> |
| | | <p>解得 <i>k</i>≈-8 004.203,<i>c</i>≈92 255.180.</p> |
| | |
| | | <p><i>y</i>=-8 004.203×ln(3.81×10<sup>4</sup>)+92 255.180</p> |
| | | <p>≈7 827.090.</p> |
| | | <p> |
| | | 所以,当大气压强为3.81×10<sup>4</sup> <i>Pa</i>时,海拔高程约为7 827.090 |
| | | m. |
| | | 所以,当大气压强为3.81×10<sup>4</sup> <i>Pa</i>时,海拔高程约为7 |
| | | 827.090 m. |
| | | </p> |
| | | <p>(2) 把<i>y</i>=8 844.43代入①式,</p> |
| | | <p class="center">8 844.43=-8 004.203 ln <i>x</i>+92 255.180,</p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 145 --> |
| | | <div class="page-box" page="152"> |
| | | <div v-if="showPageList.indexOf(152) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>145</span></p> |
| | | <p><span>145-146</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p> |
| | | 1.一部价值4 650元的手机,若每年的折旧率为30%,三年后其价值为多少元? |
| | | </p> |
| | | <p> |
| | | 2.某工厂年产值为800万元,计划从今年起,年产值平均增长率为25%,写出年产值随年数变化的函数关系式,并求三年后其年产值是原来的多少倍(结果取整数). |
| | | </p> |
| | | <p> |
| | | 3.某种放射性物质,每经过1年剩留的质量约是原来的90%.大约经过几年,剩留的质量是原来的一半? |
| | | </p> |
| | | <examinations :cardList="questionData[152] ? questionData[152][1] : []" :hideCollect="true" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | <h3 id="c047">习题4.5<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p> |
| | | 1.一种按复利计算的储蓄(复利指每年的利息转入下一年的本金参与计息),设本金为<i>a</i>元,年利率为<i>r</i>,本利和为<i>y</i>元,存期为<i>x</i>年.写出<i>y</i>随存期<i>x</i>变化的函数关系式.如果存入本金2 |
| | | 000元,年利率为2.25%,那么存满四年的本利和是多少? |
| | | </p> |
| | | <p> |
| | | 2.用清水漂洗衣服,若每次能洗去污垢的<math display="0"> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>,写出存留污垢<i>y</i>与漂洗次数<i>x</i>的函数关系式.若要使存留的污垢不超过原有的<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>64</mn> |
| | | </mfrac> |
| | | </math>,则至少要漂洗几次? |
| | | </p> |
| | | <p> |
| | | 3.我们知道,候鸟每年秋天都要从北方飞向南方过冬.假如某种候鸟的飞行速度<i>y</i>(<i>m</i>/<i>s</i> |
| | | ) 可以表示为函数<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mn>5</mn> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>x</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | </math>,其中<i>x</i>表示这种候鸟的耗氧量的单位数. |
| | | </p> |
| | | <p>(1) 当这种候鸟的飞行速度为15 m/s 时,它的耗氧量是多少单位;</p> |
| | | <p>(2) 当这种候鸟的耗氧量是40个单位时,它的飞行速度是多少?</p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p> |
| | | 1.当代中国青年生逢其时,施展才干的舞台无比广阔,实现梦想的前景无比光明.广大青年要立志做有理想、敢担当、能吃苦、肯奋斗的新时代好青年.假设给你一笔无息贷款资金用于创业投资,现有三种创业投资方案供你选择,这 |
| | | </p> |
| | | <examinations :cardList="questionData[152] ? questionData[152][2] : []" :hideCollect="true" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 146 --> |
| | | <div class="page-box" page="153"> |
| | | <div v-if="showPageList.indexOf(153) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>146</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | <p> |
| | | 三种创业方案的回报如下. |
| | | </p> |
| | | <p>方案一:每天回报40元.</p> |
| | | <p>方案二:第一天回报10元,以后每天比前一天多回报10元.</p> |
| | | <p>方案三:第一天回报0.4元,以后每天的回报比前一天翻一番.</p> |
| | | <p>请问,你会选择哪种创业投资方案?</p> |
| | | <p> |
| | | 2.某护士在工作中按治疗方案给病人注射相关药液,有一种药在病人血液中的含量保持在1 |
| | | 500mg以上时才有疗效,而低于500 |
| | | mg时病人就会有危险.该护士现给某病人注射了这种药2 500 |
| | | mg,如果该药在血液中以每小时20%的比例衰减,那么该护士应该在什么时间范围再向该病人注射这种药(结果精确到0.1h)? |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <div class="page-box hidePage" page="153"></div> |
| | | <!-- 147 --> |
| | | <div class="page-box" page="154"> |
| | | <div v-if="showPageList.indexOf(154) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <h2 id="b027">数学园地<span class="fontsz1">>>>>>>>></span></h2> |
| | | <h2 id="b027"> |
| | | 数学园地<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <p class="center">我们身边的“指数爆炸”</p> |
| | | <p> |
| | | “指数爆炸”不是真正的爆炸,是事物数量的变化呈现爆炸式急剧增长时的现象.用数学语言描述该现象时,可用指数函数模型<i>f</i>(<i>x</i>)=<i>ka<sup>x</sup></i>(<i>a</i>>1)来刻画这种变化规律,这种增长方式也叫作“指数增长”. |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 148 --> |
| | | <div class="page-box" page="155"> |
| | | <div v-if="showPageList.indexOf(155) > -1"> |
| | |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <h2 id="b028">单元小结<span class="fontsz1">>>>>>>>></span></h2> |
| | | <h2 id="b028"> |
| | | 单元小结<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <p class="bj2"><b>学习导图</b></p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0159-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0159-1.jpg" /> |
| | | </p> |
| | | <p class="bj2"><b>学习指导</b></p> |
| | | <p>1.实数指数幂.</p> |
| | | <p>(1) 正整数、负整数、分数、指数幂的意义.</p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 149 --> |
| | | <div class="page-box" page="156"> |
| | | <div v-if="showPageList.indexOf(156) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | |
| | | ax</i>(<i>a</i>>0,且<i>a</i>≠1)的函数叫对数函数. |
| | | </p> |
| | | <p>(2) 图像和性质.</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0160-5.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0160-5.jpg" /> |
| | | </p> |
| | | <p>4.指数函数与对数函数的实际应用.</p> |
| | | <p> |
| | | 分析实例背景,建立指数函数或对数函数模型,并利用指数函数、对数函数的图像及基本性质解决简单的实际问题.体会“指数爆炸”与“指数衰减”的特点. |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 150 --> |
| | | <div class="page-box" page="157"> |
| | | <div v-if="showPageList.indexOf(157) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>150</li> |
| | | <li>150-152</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <h2 id="b029">单元检测<span class="fontsz1">>>>>>>>></span></h2> |
| | | <h2 id="b029"> |
| | | 单元检测<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p>1.选择题.</p> |
| | | <p>(1) 下列函数中,( )是指数函数.</p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msup> |
| | | <mi>x</mi> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<i>y</i>=2×3<i><sup>x</sup></i> |
| | | </p> |
| | | <p> |
| | | D.<i>y</i>=-3<i><sup>x</sup></i> |
| | | </p> |
| | | <p>(2) 下列运算中错误的是( ).</p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>27</mn> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>9</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <msup> |
| | | <mn>0.25</mn> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mroot> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>16</mn> |
| | | </mfrac> |
| | | <mn>5</mn> |
| | | </mroot> |
| | | <mo>=</mo> |
| | | <msup> |
| | | <mn>2</mn> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math> |
| | | </p> |
| | | <p>D.2<sup>-3</sup>=-8</p> |
| | | <p>(3) 下列式子中,计算结果正确的是( ).</p> |
| | | <p>A.<i>a</i><sup>6</sup>÷<i>a</i><sup>3</sup>=<i>a</i><sup>2</sup></p> |
| | | <p>B.<i>a</i><sup>6</sup><i>a</i><sup>3</sup>=<i>a</i><sup>18</sup></p> |
| | | <p>C.(<i>a</i><sup>6</sup>)<sup>3</sup>=<i>a</i><sup>18</sup></p> |
| | | <p>D.<i>a</i><sup>3</sup>+<i>a</i><sup>3</sup>=<i>a</i><sup>6</sup></p> |
| | | <p>(4) 下列各式成立的是( ).</p> |
| | | <p>A.log<sub>2</sub>(8-4)=log<sub>2</sub>8-log<sub>2</sub>4</p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>8</mn> |
| | | </mrow> |
| | | <mrow> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>4</mn> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mn>8</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p>C.log<sub>2</sub>8=3log<sub>2</sub>2</p> |
| | | <p>D.log<sub>2</sub>(8+4)=log<sub>2</sub>8+log<sub>2</sub>4</p> |
| | | <p> |
| | | (5) 若<math display="0"> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>></mo> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>,则<i>a</i>的取值范围是( ). |
| | | </p> |
| | | <p>A.0<<i>a</i><1</p> |
| | | <p>B.<i>a</i>>1</p> |
| | | <p>C.<i>a</i><-1</p> |
| | | <p>D.<i>a</i><0</p> |
| | | <p> |
| | | (6) 已知log<i><sub>a</sub></i>9=2,则<i>a</i>的值为( ). |
| | | </p> |
| | | <p>A.3</p> |
| | | <p>B.-3</p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p>D.±3</p> |
| | | <p>(7)(-2)<sup>100</sup>+(-2)<sup>101</sup>=( ).</p> |
| | | <p>A.1</p> |
| | | <p>B.-1</p> |
| | | <p>C.2<sup>100</sup></p> |
| | | <p>D.-2<sup>100</sup></p> |
| | | <p>(8) 已知<i>a</i>><i>b</i>>0,则下列不等式一定成立的是( ).</p> |
| | | <p>A.lg <i>a</i><lg <i>b</i></p> |
| | | <p>B.log <sub>0.3</sub><i>a</i>>log <sub>0.3</sub><i>b</i></p> |
| | | <p> |
| | | C.3<i><sup>a</sup></i>>3<i><sup>b</sup></i> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>a</mi> |
| | | </mrow> |
| | | </msup> |
| | | <mo>></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math> |
| | | </p> |
| | | <p>2.求下列各式中<i>x</i>的值.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <msup> |
| | | <mn>2</mn> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>16</mn> |
| | | </mfrac> |
| | | </math>;(2) log <sub>3</sub><i>x</i>=2;(3) |
| | | <math display="0"> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>;(4) ln<i>x</i>=-2. |
| | | </p> |
| | | <examinations :cardList="questionData[157]" :hideCollect="true" sourceType="json" inputBc="#d3edfa" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 151 --> |
| | | <div class="page-box" page="158"> |
| | | <div v-if="showPageList.indexOf(158) > -1"> |
| | | |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第四单元 指数函数与对数函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>151</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | <p>3.比较大小.</p> |
| | | <p> |
| | | (1)<math display="0"> |
| | | <msubsup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>—</mo> |
| | | <mo>—</mo> |
| | | <mo>—</mo> |
| | | <mo>—</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>0.6</mn> |
| | | </mrow> |
| | | </msubsup> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>0.7</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <msubsup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>—</mo> |
| | | <mo>—</mo> |
| | | <mo>—</mo> |
| | | <mo>—</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>0.2</mn> |
| | | </mrow> |
| | | </msubsup> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>0.2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msub> |
| | | <mn>0.2</mn> |
| | | <mrow> |
| | | <mo>—</mo> |
| | | <mo>—</mo> |
| | | <mo>—</mo> |
| | | <mo>—</mo> |
| | | </mrow> |
| | | </msub> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>;(4) log <sub>0.2</sub>3____0. |
| | | </p> |
| | | <p>4.计算.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mn>1</mn> |
| | | <mfrac> |
| | | <mn>7</mn> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>−</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <msup> |
| | | <mo stretchy="false">)</mo> |
| | | <mrow> |
| | | <mn>0</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <msup> |
| | | <mn>10</mn> |
| | | <mrow> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>12</mn> |
| | | <mo>+</mo> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mn>25</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <msup> |
| | | <mn>2</mn> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>27</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>18</mn> |
| | | <mo>+</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>3</mn> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (4)<math display="0"> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>100</mn> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>15</mn> |
| | | <mo>−</mo> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mn>9</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p>5.求下列函数的定义域.</p> |
| | | <p> |
| | | (1)<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msup> |
| | | <mn>3</mn> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mo>−</mo> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <msup> |
| | | <mn>2</mn> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </msup> |
| | | </mfrac> |
| | | </math>;(3) <i>y</i>=log <sub>2</sub>(3-<i>x</i>-2<i>x</i><sup>2</sup>); |
| | | </p> |
| | | <p> |
| | | (4)<math display="b0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>0.5</mn> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | </math>;(5) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <msqrt> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>0.5</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </msqrt> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 6.为了推进新型工业化,加快建设制造强国、质量强国,某新能源汽车配件公司2020年生产某种产品2万件,计划从2021年开始,每年的产量比上一年增长20%,经过多少年,该工厂生产的这种产品的年产量达到12万件? |
| | | </p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p>1.选择题.</p> |
| | | <p>(1) 下列函数中,在区间(0,+∞)内是增函数的是( ).</p> |
| | | <p>A.<i>y</i>=<i>x</i><sup>-1</sup></p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </msup> |
| | | </math> |
| | | </p> |
| | | <p>(2) log<sub>9</sub>27=( ).</p> |
| | | <p>A.3</p> |
| | | <p>B.9</p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p>(3) 已知log<sub>3</sub>(lg <i>x</i>)=0,则<i>x</i>=( ).</p> |
| | | <p>A.0</p> |
| | | <p>B.1</p> |
| | | <p>C.3</p> |
| | | <p>D.10</p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <div class="page-box hidePage" page="158"></div> |
| | | <!-- 152 --> |
| | | <div class="page-box" page="159"> |
| | | <div v-if="showPageList.indexOf(159) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>152</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | |
| | | <div class="bj"> |
| | | |
| | | <p> |
| | | (4) 已知<i>a</i>=0.7<sup>2.1</sup>,<i>b</i>=log |
| | | <sub>2</sub>0.7,<i>c</i>=2.1<sup>0.7</sup>,则它们的大小关系为( ). |
| | | </p> |
| | | <p>A.<i>a</i>><i>b</i>><i>c</i></p> |
| | | <p>B.<i>c</i>><i>a</i>><i>b</i></p> |
| | | <p>C.<i>c</i>><i>b</i>><i>a</i></p> |
| | | <p>D.<i>b</i>><i>c</i>><i>a</i></p> |
| | | <p> |
| | | (5) 函数<i>y</i>=3-2<i><sup>x</sup></i>的值域为( ). |
| | | </p> |
| | | <p>A.(-∞,3)</p> |
| | | <p>B.(-∞,+∞)</p> |
| | | <p>C.(0,+∞)</p> |
| | | <p>D.(3,+∞)</p> |
| | | <p class="center"> |
| | | <img class="img-f" alt="" src="../../assets/images/0163-1.jpg" /> |
| | | </p> |
| | | <p class="img">第1(6)题图</p> |
| | | <p> |
| | | (6) 函数<i>y</i>=<i>a<sup>x+b</sup></i>(<i>a</i>>0,且<i>a</i>≠1)的图像如图所示,则<i>a</i>,<i>b</i>的范围是( ). |
| | | </p> |
| | | <p>A.<i>a</i>>1,<i>b</i>>0</p> |
| | | <p>B.<i>a</i>>1,<i>b</i><0</p> |
| | | <p>C.0<<i>a</i><1,<i>b</i>>0</p> |
| | | <p>D.0<<i>a</i><1,<i>b</i><0</p> |
| | | <p>2.计算.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <msup> |
| | | <mn>3</mn> |
| | | <mrow> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>−</mo> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>0.1</mn> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>−</mo> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>2</mn> |
| | | <mo>×</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>10</mn> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <msup> |
| | | <mi>b</mi> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo>⋅</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mi>a</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <msup> |
| | | <mi>b</mi> |
| | | <mrow> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msup> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <msqrt> |
| | | <mn>27</mn> |
| | | </msqrt> |
| | | <mo>⋅</mo> |
| | | <mroot> |
| | | <mn>9</mn> |
| | | <mn>3</mn> |
| | | </mroot> |
| | | <mo>÷</mo> |
| | | <mroot> |
| | | <mn>3</mn> |
| | | <mn>6</mn> |
| | | </mroot> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (4) |
| | | <math display="0"> |
| | | <mi>lg</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msqrt> |
| | | <mn>1000</mn> |
| | | </msqrt> |
| | | <mo>+</mo> |
| | | <msub> |
| | | <mi>log</mi> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | </mrow> |
| | | </msub> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 3.已知log<sub>6</sub>3=<i>a</i>,6<i><sup>b</sup></i>=5. |
| | | </p> |
| | | <p> |
| | | (1) 求6<i><sup>2a-b</sup></i>的值;(2) 用<i>a</i>,<i>b</i>表示log<sub>6</sub>45的值. |
| | | </p> |
| | | <p> |
| | | 4.死亡动植物体内的碳14的含量会有规律地不断减少,利用这种变化规律可以测定动植物的死亡年代,其计算公式是<math display="0"> |
| | | <mi>M</mi> |
| | | <mo>=</mo> |
| | | <msub> |
| | | <mi>M</mi> |
| | | <mrow> |
| | | <mn>0</mn> |
| | | </mrow> |
| | | </msub> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mfrac> |
| | | <mi>t</mi> |
| | | <mn>5730</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | </msup> |
| | | </math>,其中<i>M</i>是某生物死亡后的碳14的含量,<i>M</i><sub>0</sub>是该生物活着时碳14的含量,<i>t</i>是该生物死亡后到现在的年数.现有一颗古树的化石,测得其碳14的含量只有这棵古树活着时的5%.这棵古树的死亡时间距今大约多少年?(结果精确到1年) |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <div class="page-box hidePage" page="159"></div> |
| | | </div> |
| | | </template> |
| | | |
| | | <script> |
| | | import examinations from "@/components/examinations/index.vue"; |
| | | export default { |
| | | name: '', |
| | | name: "", |
| | | props: { |
| | | showPageList: { |
| | | type: Array, |
| | | default: [], |
| | | }, |
| | | questionData: { |
| | | type: Object, |
| | | }, |
| | | }, |
| | | components: {}, |
| | | components: { examinations }, |
| | | data() { |
| | | return {} |
| | | return {}; |
| | | }, |
| | | computed: {}, |
| | | watch: {}, |
| | | created() { }, |
| | | mounted() { }, |
| | | methods: {}, |
| | | } |
| | | }; |
| | | </script> |
| | | |
| | | <style lang="less" scoped></style> |