2除以sin2θ+cos(π+θ)除以cos(π除以2-θ)化简
问题描述：
2除以sin2θ+cos(π+θ)除以cos(π除以2-θ)化简
答
(2/sin2θ)+[cos(π+θ)/cos(π/2-θ)]化简
原式=(1/sinθcosθ)+(-cosθ/sinθ)=(1-cos²θ)/sinθcosθ=sin²θ/sinθcosθ=sinθ/cosθ=tanθ
答
2除以sin2θ+cos(π+θ)除以cos(π除以2-θ)=2/sin2θ+cos(π+θ)/cos(π/2-θ)=2/sin2θ-cosθ/cos(π/2-θ)=2/sin2θ-cosθ/sinθ=2/sin2θ-2cosθcosθ/2sinθcosθ=2/sin2θ-2cos^2θ/sin2θ=(2-2cos^2θ)/sin2...