自主录题

自主录题一试题标签

省市校区

阶段科目

题型题类

年份题源

存放类型

已选考点

难度系数

一星二星三星四星五星

在线训练

是否

自主录题一试题内容

试题内容

题型种类

选择题 非选择题

选项效果

一行4选项 一行2选项 一行1选项

选项内容

A B C D E F G H

选择答案

自主录题一试题解答

试题解答

<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">解：（1）由题意知：</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">当0＜<i>x</i>≤1时，<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">甲</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">＝22<i>x</i>；</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">当1＜<i>x</i>时，<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">甲</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">＝22+15（<i>x</i>﹣1）＝15<i>x</i>+7．</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><i><span style="line-height:150%"><span style="font-family:宋体">y</span></span></i><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">乙</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">＝16<i>x</i>+3．</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">（2）①当0＜<i>x</i>≤1时，</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">令<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">甲</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">＜<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">乙</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">，即22<i>x</i>＜16<i>x</i>+3，</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">解得：0＜<i>x</i>＜</span></span></span></span></span><img height="35" src="/uploads/meth/20210328/4fb557c1880cb3bac0f3435e9901e15a.png" width="13" /><span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">；</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">令<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">甲</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">＝<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">乙</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">，即22<i>x</i>＝16<i>x</i>+3，</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">解得：<i>x</i>＝</span></span></span></span></span><img height="35" src="/uploads/meth/20210328/cda4afaea4f4e163397155464b08f5f3.png" width="13" /><span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">；</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">令<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">甲</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">＞<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">乙</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">，即22<i>x</i>＞16<i>x</i>+3，</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">解得：</span></span></span></span></span><img height="35" src="/uploads/meth/20210328/bdd1227eeec892fc261832cce0bd6104.png" width="13" /><span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">＜<i>x</i>≤1．</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">②<i>x</i>＞1时，</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">令<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">甲</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">＜<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">乙</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">，即15<i>x</i>+7＜16<i>x</i>+3，</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">解得：<i>x</i>＞4；</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">令<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">甲</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">＝<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">乙</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">，即15<i>x</i>+7＝16<i>x</i>+3，</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">解得：<i>x</i>＝4；</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">令<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">甲</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">＞<i>y</i></span></span><sub><span style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:宋体">乙</span></span></span></sub><span style="line-height:150%"><span style="font-family:宋体">，即15<i>x</i>+7＞16<i>x</i>+3，</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">解得：1＜<i>x</i>＜4．</span></span></span></span></span><br />
<span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">综上可知：当</span></span></span></span></span><img height="35" src="/uploads/meth/20210328/242e7ff836c76f53c0907783c4fb9df7.png" width="13" /><span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">＜<i>x</i>＜4时，选乙快递公司省钱；当<i>x</i>＝4或<i>x</i>＝</span></span></span></span></span><img height="35" src="/uploads/meth/20210328/c10fa58620ec34ae6e516477920b3d3d.png" width="13" /><span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">时，选甲、乙两家快递公司快递费一样多；当0＜<i>x</i>＜</span></span></span></span></span><img height="35" src="/uploads/meth/20210328/a537051b8962a1b1f37acdb4d48f104b.png" width="13" /><span style="font-size:10.5pt"><span style="line-height:150%"><span style="font-family:Calibri"><span style="line-height:150%"><span style="font-family:宋体">或<i>x</i>＞4时，选甲快递公司省钱．</span></span></span></span></span>

自主录题一试题点评

智能点评

手动点评