I thought you needed a trig identity and I guess you gotta substitutes Could anyone just give me a clue (please©05 BE Shapiro Page 3 This document may not be reproduced, posted or published without permission The copyright holder makes no representation about the accuracy, correctness, orLet's use integration by parts If we apply integration by parts to the rightmost expression again, we will get $∫\cos^2(x)dx = ∫\cos^2(x)dx$, which is not very useful The trick is to rewrite the $\sin^2(x)$ in the second step as $1\cos^2(x)$ Then we get
Integral Of The Secant Function Wikipedia