若tan(兀-α)=2,则2sin(3兀+α)cos(5/2兀+α)+sin(3/2兀-α)sin(兀-α)=?

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若tan(兀-α)=2,则2sin(3兀+α)cos(5/2兀+α)+sin(3/2兀-α)sin(兀-α)=?若tan(兀-α)=2,则2sin(3兀+α)cos(5/2兀+α)+sin(3/2兀-

若tan(兀-α)=2,则2sin(3兀+α)cos(5/2兀+α)+sin(3/2兀-α)sin(兀-α)=?
若tan(兀-α)=2,则2sin(3兀+α)cos(5/2兀+α)+sin(3/2兀-α)sin(兀-α)=?

若tan(兀-α)=2,则2sin(3兀+α)cos(5/2兀+α)+sin(3/2兀-α)sin(兀-α)=?
因为:tan(π-a)=2,所以:tana=-2
2sin(3π+a)cos(5/2π+a)+sin(3/2π-a)sin(π-a)
=+2sinasina-cosasina=[2(sina)^2-sinacosa]/[(sina)^2+(cosa)^2]
=[2(tana)^2-tana]/[(tana)^2+1]
=[2(-2)^2-(-2]/[(-2)^2+1]=2