(sin2θ+ sinθ)/(cos2θ+ cosθ+ 1)
问题描述:
(sin2θ+ sinθ)/(cos2θ+ cosθ+ 1)
答
原式=[2sinacosa+sina]/[(2cos²a-1)+cosa+1]
=[sina(2cosa+1)]/[cosa(2cosa+1)]
=sina/cosa
=tana