函数y=sin2x+cos2x的值域?

问题描述:

函数y=sin2x+cos2x的值域?

y=sin2x+cos2x
=根号2(根号2*sin2x/2+根号2*cos2x/2)
=根号2(sin2x*cos45°+cos2x*cos45°)
=根号2*sin(2x+45°)∈[-根号2,根号2]
不知现在你明白了(⊙_⊙)?