(2sin2α/1+cos2α)*(cos^2/cos2α)=?

问题描述:

(2sin2α/1+cos2α)*(cos^2/cos2α)=?

(2sin2α/1+cos2α)*(cosα)^2/cos2α
=2tana*(cosα)^2/cos2α
=2tana*(cosα)^2/cos2α
=2sinα*cosα/cos2α
=sin2α/cos2α
=tan2a