题目

sin(π-θ）+cos(2π-θ）/cos(5π/2-θ)+sin(3π/2+θ)=2,则sinθcosθ=______

提问时间：2020-07-24

答案

[sin(π-θ)+cos(2π-θ)]/[cos(5π/2-θ)+sin(3π/2+θ)]=2=(sinθ+cosθ)/(sinθ-cosθ)=2
sinθ=3cosθ
tanθ=3
sinθ*cosθ=sinθcosθ/[sin^θ+cos^θ]=tanθ/[tan^θ+1]=3/10