$\int \frac{4}{x(\ln x+1)^{2}} d x$
\(-\frac{4}{\ln x + 1} + C\)
Step 1 :\(u = \ln x + 1\)
Step 2 :\(\frac{d u}{d x} = \frac{1}{x}\)
Step 3 :\(\int \frac{4}{x(u)^{2}} d x = 4 \int \frac{1}{u^2} d u\)
Step 4 :\(-4u^{-1} + C = -\frac{4}{u} + C\)
Step 5 :\(-\frac{4}{\ln x + 1} + C\)