I'm currently stuck with trying to find the answer for the integral of 2cosec^2(2x) between the values of pi/4 and pi/6.

I can integrate it and get -cot(2x) but when I put the values in I get a math error because cot(2x) is 1/tan(2x) and therefore if I put pi/4 in it will never have an answer.

I can get the answer from the back of the book but I am more interested (and in need of knowing) in how to get it.