Производная от y=((x-1)/(x+1))^2

Как-то так вроде.f'(y)=(((x-1)/(x+1))^2)’ * ((x-1)/(x+1))’=2((x-1)/(x+1)) * ((x-1)'(x+1)-(x-1)(x+1)’)/(x+1)^2=2((x-1)/(x+1)) * ((1-0)(x+1)-(x-1)(1+0))/(x+1)^2=2((x-1)/(x+1)) * (x+1-x+1)/(x+1)^2=2((x-1)/(x+1)) *2/(x+1)^2