2sinθ-cosθ=1 (sinθ+cosθ+1)/(sinθ-cosθ+1)
问题描述：
2sinθ-cosθ=1 (sinθ+cosθ+1)/(sinθ-cosθ+1)
如题
已知2sinθ-cosθ=1 求(sinθ+cosθ+1)/(sinθ-cosθ+1)
答
(sinθ+cosθ+1)/(sinθ-cosθ+1) =(sinθ+cosθ+2sinθ-cosθ)/(sinθ-cosθ+2sinθ-cosθ) =3sinθ/(3sinθ-2cosθ) 2sinθ-cosθ=1(2sinθ -cosθ)^2=1=sin^2θ+cos^2θ化简得到：3sin^2θ-4sinθcosθ=0...