Evaluate
above equation can be solve by using one formula that is (i+ tan2x=sec2x)
I = ∫ sec4x dx
= ∫ sec2x sec2x dx
= ∫ sec2x ( 1 + tan2x ) dx
= ∫ sec2x dx + ∫ sec2x tan2x dx
Put tanx=t in above equation so that sec2xdx=dt