sin^2 30°+cos()=1
求证:sin^2/(sin-cos) - (sin+cos)/(tan^2 -1) =sin+cos
求证sinθ/(1+cosθ)+(1+cosθ)/sinθ=2/sinθ
sinα=-2cosα,求sin^2α-3sinαcosα+1
证明Cos^A-Sin^A=1-2Sin^A=2Cos^A-1=cos^a-sin^a
求证:(1+cosθ+cosθ/2) /(sinθ+sinθ/2)=sinθ/1-cosθ
sinα^2+sinβ^2+sinγ^2=1,那么cosαcosβcosγ最大值等于
已知3sinα=cosα,则sinα-2sinαcosα+3cosα+1=
求证(1+sinα+cosα+2sincosα)/(1+sinα+cosα)=sinα+cosα
已知tan∝=2/3,求值:(1)(cos∝-sin∝/cos∝+sin∝)+(cos∝+sin
求证(1-sinθcosθ)除以(cos^2θ-sin^2θ)=(cos^2θ-sin^2θ)除以(1+2sinθcos
求证:(cosβ/(1+sinβ))-(sinβ/(1+cosβ))=(2cosβ-2sinβ)/(1+sinβ+cos
求证(1+sinθ+cosθ)/(1+sinθ-cosθ)+(1-cosθ+sinθ)/(1+cosθ+sinθ)=2/