化简：（1tanα2-tanα2）•1−cos2αsin2α．

Question

化简：（(1)/(tan(α)/(2))-tan(α)/(2)）•(1−cos2α)/(sin2α)．

Answer 1

原式=（(cos(α)/(2))/(sin(α)/(2))-(sin(α)/(2))/(cos(α)/(2))）•（(1−cos2α)/(sin2α)）
=(cos2(α)/(2)−sin2(α)/(2))/(sin(α)/(2)•cos(α)/(2))•(2sin2α)/(2sinαcosα)
=(2cosα)/(sinα)•(sinα)/(cosα)=2