Question

integrate (1/x^2) cos^2 (1/x) dx

Answer 1

\(u=\frac{1}{x}\) is a start, and you get \(du=-\frac{dx}{x^2}\) so you are in luck

Answer 2

okok. get it

Answer 3

then how to integrate the cos^2??

Answer 4

cos^2 u = (cos2u +1)/2 = (cos2u)/2 + 1/2 <- int this