若(sinθ+cosθ)/(sinθ-cosθ)=2,则sinθcosθ的值是

网友回答

sinθ+cosθ=2(sinθ-cosθ)
sinθ+cosθ=2sinθ-2cosθ
sinθ=3cosθ
sinθ/cosθ=3
tanθ=3
sinθcosθ
=1/2*sin2θ
=1/2*2tanθ/[1+(tanθ)^2]
=tanθ/[1+(tanθ)^2]
=3/(1+3^2)
=3/10