2019-2020学年河南省三门峡市高二上学期期末考试数学理科试题 Word版含解析

12-10|数学

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2019-2020学年度上学期期末调研考试高二数学(理科)

一、选择题

1.已知a,b,c为实数,则下列结论正确的是( )

A. 若 EMBED Equation.DSMT4 ,则 EMBED Equation.DSMT4 B. 若 EMBED Equation.DSMT4 ,则 EMBED Equation.DSMT4

C. 若 EMBED Equation.DSMT4 , EMBED Equation.DSMT4 ,则 EMBED Equation.DSMT4 D. 若 EMBED Equation.DSMT4 ,则 EMBED Equation.DSMT4

【答案】C

【解析】

【分析】

根据不等式的性质,对各选项逐个判断即可得出.

【详解】对A,若 EMBED Equation.DSMT4 ,当 EMBED Equation.DSMT4 时,则 EMBED Equation.DSMT4 ,当 EMBED Equation.DSMT4 时,则 EMBED Equation.DSMT4 ,所以A错误;

对B,若 EMBED Equation.DSMT4 ,当 EMBED Equation.DSMT4 时,则 EMBED Equation.DSMT4 ,当 EMBED Equation.DSMT4 时, EMBED Equation.DSMT4 ,

当 EMBED Equation.DSMT4 时,则 EMBED Equation.DSMT4 ,所以B错误;

对C,若 EMBED Equation.DSMT4 , EMBED Equation.DSMT4 ,则 EMBED Equation.DSMT4 ,C正确;

对D,若 EMBED Equation.DSMT4 ,当 EMBED Equation.DSMT4 时,则 EMBED Equation.DSMT4 ,当 EMBED Equation.DSMT4 时,则 EMBED Equation.DSMT4 ,所以D错误;

故选:C.

【点睛】本题主要考查不等式的性质应用,属于基础题.

2.命题“若 EMBED Equation.DSMT4 ,则 EMBED Equation.DSMT4 且 EMBED Equation.DSMT4 ”的否命题为( )

A. 若 EMBED Equation.DSMT4 ,则 EMBED Equation.DSMT4 且 EMBED Equation.DSMT4

B. 若 EMBED Equation.DSMT4 ,则 EMBED Equation.DSMT4 或 EMBED Equation.DSMT4

C. 若 EMBED Equation.DSMT4 ,则 EMBED Equation.DSMT4 且 EMBED Equation.DSMT4