y=[ln(1-x)^2]^2
y'= 2[ln(1-x)^2] * [ln(1-x)^2]'
= 2[ln(1-x)^2] * [2ln(1-x)]'
= 2[ln(1-x)^2] * 2*1/(1-x)
= 4*[ln(1-x)^2]/(1-x)