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



44