1-sin2a-cos^2(a-π/4)
问题描述：
1-sin2a-cos^2(a-π/4)
答
1-sin2a-cos^2(a-π/4)
=sin^2(a-π/4)-sin2a
=(根号2sina-根号2cosa)^2-sin2a
=2(cosa^2-2sinacosa+cosa^2)-sin2a
=2(1-sin2a)-sin2a
=2-3sin2a