Identidades del ángulo doble

Topic Notes
Fórmulas:
sen(2θ)=2 senθcos⁡θ sen (2\theta) = 2 \, sen\theta\cos\theta
cos⁡2θ=cos⁡2θ−sen2θ \cos 2 \theta = {\cos ^2}\theta - {sen^2}\theta
=  2cos⁡2θ−1 = \;2{ \cos ^2}\theta - 1
=  1−2sen2θ = \;1 - 2{sen ^2}\theta
tan⁡2θ=2tan⁡θ1−tan⁡2θ \tan 2 \theta = {{2\tan \theta} \over {1 - \tan ^2}\theta}