函数y=cos^2x-sin^2x+2sinxcosx(x∈R)的值域为
问题描述:
函数y=cos^2x-sin^2x+2sinxcosx(x∈R)的值域为
答
y=cos^2x-sin^2x+2sinxcosx
=cos2x+sin2x
=根号2 sin(2x+π/4)
-1