sin2a-2cos^2 a/sin(a-π/4)=?化简

问题描述:

sin2a-2cos^2 a/sin(a-π/4)=?化简

(sin2a-2cos^2 a)/sin(a-π/4)
=(2sinacosa-2cos²a)/(sinacosπ/4-cosasinπ/4)
=2cosa(sina-cosa)/[√2/2·(sina-cosa)]
=2√2·cosa