求证sin^2(π/4+α)=cos^2(π/4-α)

问题描述:

求证sin^2(π/4+α)=cos^2(π/4-α)


sin²(π/4+a)
=sin²[π/2-(π/4-a)]——sin(π/2-a)=cosa
=cos²(π/4-a)