1−tan2θ1+tan2θ\frac{1-\tan ^{2} \theta}{1+\tan ^{2} \theta}1+tan2θ1−tan2θ
1+tan2θ2tanθ\frac{1+\tan ^{2} \theta}{2 \tan \theta}2tanθ1+tan2θ
2tanθ1+tan2θ\frac{2 \tan \theta}{1+\tan ^{2} \theta}1+tan2θ2tanθ
tanθ1+tan2θ\frac{\tan \theta}{1+\tan ^{2} \theta}1+tan2θtanθ