Given Definite Integral can be written as:

Let us assume tan^-1x = y

Differentiating w.r.t x on both sides we get,

⇒ d(tan^-1x) = d(y)

Upper limit of the Definite Integral:

⇒ x = 1 ⇒ y = tan^-1(1)

Lower limit of the Definite Integral:

⇒ x = 0 ⇒ y = tan^-1(0)

⇒ y = 0…… (4)

Substituting (2),(3),(4) in the eq(1) we get,

We know that:

We know that:

[here f’(x) is derivative of f(x))