已知f(x)=(x+1)/(x-1)(x不等于正负1),则f(-x)=( )
问题描述:
已知f(x)=(x+1)/(x-1)(x不等于正负1),则f(-x)=( )
A 1/f(x) B -f(x)
C -1/f(x) D -f(-x)
答
f(-z)=(-x+1)/(-x-1)
=(-(x-1))/(-(x+1))
=(x-1)/(x+1)
=1/f(x)