化简cosasin^2a/sin^2-cos^2a

化简cosasin^2a/sin^2-cos^2a+sina/1-tan^2a

1个回答

cosa(sina)^2/[(sina)^2-(cosa)^2]+sina/[1-(tana)^2]
=[-cosa(sina)^2+sina(cosa)^2]/[(cosa)^2-(sina)^2]
=sinacosa(cosa-sina)/[(cosa-sina)(cosa+sina)]
=sinacosa/(cosa+sina).