化简 (1-2sin@cos@)/(cos@^2-sin@^2)*(1+2sin@cos@)/(1-2sin@^2) 两
化简 (1-2sin@cos@)/(cos@^2-sin@^2)*(1+2sin@cos@)/(1-2sin@^2) 两
求证:sin^2/(sin-cos) - (sin+cos)/(tan^2 -1) =sin+cos
化简:1+sinθ+cosθ+2sinθcosθ /1+sinθ+cosθ
化简sin²α-2sinαcosα+1
化简Sin A + Sin 2A / 1+cos A +
2sin@+cos@等于?
化简[1-(sin^4x-sin^2cos^2x+cos^4x)/(sin^2)]+3sin^2x
化简:(1)sin(α+β)−2sinαcosβ2sinαsinβ+cos(α+β)
sinα=-2cosα,求sin^2α-3sinαcosα+1
求证sinθ/(1+cosθ)+(1+cosθ)/sinθ=2/sinθ
1/2sin α cos α 为什么等于sin α
求证sin^2α+sin^2β-sin^2αsin^2β+cos^2cos^2β=1