设函数2^Ix+1I-Ix-1I,求使f(x)>=2√2的X取值
问题描述：
设函数2^Ix+1I-Ix-1I,求使f(x)>=2√2的X取值
答
f(x)=2^|x+1|-|x-1|求使f(x)≥2√2的X取值解:∵2√2=2^(3/2)∴原式等价于f(x)≥2^(3/2)因为函数2^x是单调递增函数∴f(x)=2^|x+1|-|x-1|≥2^(3/2)等价于|x+1|-|x-1|≥3/2解不等式|x+1|-|x-1|≥3/2①x-1≥0即x≥1时：...