2018年郴州市中考数学模拟试题答案.docx

2018年郴州市初中毕业学业考试模拟试卷数学参考答案及评分标准说明：如果考生的解法与本答案的解法不同，可参照本答案的评分意见给分.评卷中，不要因解答中出现错误而中断对该题的评阅，当解答中某一步出错影响了后继部分，但该步以后的解未改变这道题的内容和难度，在未发生新的错误前，可视影响的程度决定后面部分的记分，但不应超过后面部分应给分数的一半，如有严重错误，就不记分.各题解答中右端所给分数，表示考生正确做到这步应得的累加分数.一、选择题（共8小题，每小题3分，共24分）1—5 BCADD 6—8 CBA二、填空题（共8小题，每小题3分，共24分）9. 10. 且11. 12. 乙13. 14. 45°15. 16. 7三、解答题（17～19题每题6分，20～23题每题8分，24～25题每题10分，26题12分，共82分）17. 解：原式····································4分（每一知识点1分）·······························································5分·············································································2分解：原式·····················································2分·······································································3分 ················································································4分 ················································································5分当时，原式··························································6分证明：如图，∵ 四边形ABCD是平行四边形， ∴ AB∥DC，AB＝DC．………………………… 1分∵ DE＝AB，∴ DE＝DC． ∴ ∠DCE＝∠DEC．…………………………3分∵ AB∥DC，∴ ∠ABC＝∠DCE． ∴ ∠ABC＝∠DEC． …………………………4分又∵ AB＝DE，BE＝EB，∴ △ABE≌△DEB． …………………………5分∴ AE＝BD．…………………………6分解：（1）200·······················································································2分（2）图1和图2补充如下：3060·····················4分小说所对应的圆心角度数为：360°×20％＝72°···········································6分（3）800×40％＝320（人）······································································7分答：全校学生中最喜欢漫画人数约为320人。···············································8分解：（1）设一件A商品的进价为元，由题意可得：解得：经检验，是原方程的根此时，所以一件A型商品的进价为160元，B型商品的进价为150元.·························2分（2）设A型商品m件，B型商品（250－m）件，则 解得80≤m≤125，函数关系式为：y＝10m＋17500（80≤m≤125）；·······························5分（3）y＝10m＋17500－ma＝（10－a）m＋17500，当0＜a＜10时，y随m的增大而增大，当m＝125时利润最大，ymax＝1250－125a＋17500＝18750－125a；当a＝10时，y＝17500，ymax＝17500；当a＞10时，y随m的增大而减小，当m＝80时，利润最大，ymax＝800－80a＋17500＝18300－80a．···········8分1分4分3分6分7分8分5分2分8分7分6分解：（1）3；···············································································