β=α1+α\beta=\frac{\alpha}{1+\alpha}β=1+αα
β=1+α1−α\beta=\frac{1+\alpha}{1-\alpha}β=1−α1+α
α=β1+β\alpha=\frac{\beta}{1+\beta}α=1+ββ
α=1+ββ\alpha=\frac{1+\beta}{\beta}α=β1+β