## Beatles 3 years ago $\int\limits \frac{\csc ^{2}(\frac{1}{x})}{x ^{2}}dx$

1. experimentX

let 1/x = u see what happens probably you get answer in cot

2. agentx5

From what @experimentX said $$u = \frac{1}{x} = x^{-1}$$ $$du = (-1)x^{-2} \ \ dx \ \rightarrow \ -du = x^{-2} \ \ dx$$ See of you can find du hidden up there ;-)