已知函数 f(x)=ex−e−x2 ， x1 、 x2 、 x3∈R ，且 x1+x2>0 ， x2+x3>0 ， x3+x1>0 ，则 f(x1)+f(x2)+f(x3) 的值_刷题宝

题干

已知函数 f(x)=

e

x

−

e

−

x

2

， x1 、 x2 、 x3∈R ，且 x1+x2>0 ， x2+x3>0 ， x3+x1>0 ，则 f(x1)+f(x2)+f(x3) 的值（）

A：一定等于零．

B：一定大于零．

C：一定小于零．

D：正负都有可能．

上一题下一题 0.0难度选择题更新时间:2019-01-01 04:29:32

答案(点此获取答案解析）

B

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