To find:

Formula Used:

1. sec² x = 1 + tan² x

2.

3. sin 2x = 2 sin x cos x

Rewriting the given equation,

Dividing by cos⁴ x in the numerator and denominator,

Let y = tan x

dy = sec² x dx

Therefore,

Let z = y²

dz = 2y dy

⇒ tan^-1 z + C

Since z = y²,

⇒ tan^-1(y²) + C

Since y = tan x,

⇒ tan^-1(tan² x) + C

Therefore,