Question

Answer 1

∫ tan³ x sec² x dx
Let tan x = t
⇒ sec² x dx = dt
Now, ∫ tan³ x sec² x dx
= ​∫ t³.dt
$$\begin{gathered} =\frac{t^4}{4}+C \\ =\frac{{\tan }^{4}x}{4}+C \end{gathered}$$