若tan(Л-α)=2,则2sin(3Л+ α)×cos(5Л/2+α)+sin(3Л/2-α)×sin(Л-α )的值为

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若tan(Л-α)=2,则2sin(3Л+ α)×cos(5Л/2+α)+sin(3Л/2-α)×sin(Л-α )的值为
若tan(Л-α)=2,则2sin(3Л+ α)×cos(5Л/2+α)+sin(3Л/2-α)×sin(Л-α )的值为

若tan(Л-α)=2,则2sin(3Л+ α)×cos(5Л/2+α)+sin(3Л/2-α)×sin(Л-α )的值为
tan(Л-α)=2,则tana=-2,sina=-2cosa
2sin(3Л+ α)×cos(5Л/2+α)+sin(3Л/2-α)×sin(Л-α )
=2(-sina)*(-sina)+(-cosa)*sina
=2(sina)^2-sinacosa
=2-2(cosa)^2-(-2(cosa)^2)
=2