Evaluate the following integrals:
∫ sec4 x tan x dx
Put tanx = t
d(tanx) = dt
sec2xdx = dt
⇒
We can write sec4x = sec2x. sec2x
Now ,the question becomes
Tan2x + 1 = sec2x
tanx = t
t2 + 1 = sec2x
But t = tanx