将y=4sin^4x+4cos^4x-3转化为y=Asin(wx+φ)的形式
问题描述:
将y=4sin^4x+4cos^4x-3转化为y=Asin(wx+φ)的形式
答
原式=4(sin^2x+cos^2x)^2-8sin^2xcos^2x-3
=1-8sin^2xcos^2x
=1-2(sin2x)^2
=cos4x