f x=根号下x2+3x-4的单调减区间是
问题描述:
f x=根号下x2+3x-4的单调减区间是
答
答:
f(x)=√(x^2+3x-4)
=√[(x+3/2)^2-25/4]
g(x)=(x+3/2)^2-25/4>=0,x>=1或者x