sin2x-cos2x是如何变换到根号2*sin(2x-兀/4)的?

问题描述:

sin2x-cos2x是如何变换到根号2*sin(2x-兀/4)的?

sin2x-cos2x
=(sin2x-cos2x)*(根2/2)*根2
=根2[sin2x*根2/2-cos2x*根2/2]
=根2[sin2x*cos派/4-cos2x*sin派/4]
=根2[sin(2x-派/4)]