sin2α-cos2α+1/1+tanα怎样化简成2sinαcosα?

sin2α-cos2α+1/1+tanα怎样化简成2sinαcosα?
sin2α-cos2α+1/1+tanα怎样化简成2sinαcosα?

sin2α-cos2α+1/1+tanα怎样化简成2sinαcosα?
=(2sinacosa+2sin^2a)/(1+sina/cosa)
=2sina*(sina+cosa)/[(sina+cosa)/cosa]
=2sina/(1/cosa)
=2sinacosa