(sin2θ+ sinθ)/(cos2θ+ cosθ+ 1)

问题描述:

(sin2θ+ sinθ)/(cos2θ+ cosθ+ 1)

原式=[2sinacosa+sina]/[(2cos²a-1)+cosa+1]
=[sina(2cosa+1)]/[cosa(2cosa+1)]
=sina/cosa
=tana