函数f(x)在[0,+无穷大)上单调递减,则f[根号(1-x^2)]的单调递减区间为?
问题描述：
函数f(x)在[0,+无穷大)上单调递减,则f[根号(1-x^2)]的单调递减区间为?
答
1-x^2≥0, -1≤x≤1
t=根号(1-x^2)在[-1,0]是增
故f[根号(1-x^2)]的单调递减区间为[-1,0]