1/tanθ + sinθ/1+cosθ

1/cosθ*sinθ等于tanθ吗 化简sinθ-cosθ/tanθ-1 化简(sinθ-cosθ)/(tanθ-1) sin^2θ/sinθ-cosθ + cosθ/1-tanθ = sin^2θ/sinθ-cosθ + cosθ/1-( 证明下列恒等式(sinθ+cosθ)/(1-tan^2θ)+sin^2θ/(sinθ-cosθ)=sinθ+cosθ 已知tanθ=根号2,求(1)(cosθ+sinθ)/(cosθ-sinθ)；（2）sin²θ-sinθcos 证明1-2cos^2θ/tanθ-cotθ=sinθcosθ 已知tan(θ+π/4)=-2,求cosθ平方+sinθcosθ-1 (1)若角θ的终边在第四象限,试判断sin(cosθ)*cos(sinθ)的符号(2)若tan(cosθ)*tan(si tanθ=2,sinθ平方+2sinθcosθ+1的值 求证[tanθ·(1-sinθ)]/1+cosθ=[cotθ·(1-cosθ)]/1+sinθ 求证 (sinθ+cosθ-1)(sinθ-cosθ+1)) /sin2θ=tanθ/2