y = (x²-2x)/x²-2x+1
x²-2x = t, t' = 2x-2
f(t)=t/t+1 = 1-1/t+1
f'(t) = t'/(t+1)²
f'(x) = (2x-2)/(x-1)⁴
y = (x²-2x)/x²-2x+1
x²-2x = t, t' = 2x-2
f(t)=t/t+1 = 1-1/t+1
f'(t) = t'/(t+1)²
f'(x) = (2x-2)/(x-1)⁴