How is tan^5 x integrated to get (1/4)sec^4(x) - tan^2(x) + ln|sec x| + C ?
I tried integrating 2 different ways and was unable to get the books answer.
When integrating trigonometric integrals with odd powers, like tan^5 x, it can be useful to factor out a tan x and then use a trig identity dealing with even powers, specifically tan^2 x