In this tutorial we will prove the formula of cotangent integral which is another important formula in integral calculus. This integral belongs to the trigonometric formulae.
The integration of the cotangent function is of the form
To prove this formula, consider
Using the derivative formula and , we have
Integrating both sides of equation (i) with respect to , we have
As we know that by definition integration is the inverse process of the derivative, the integral sign and on the right side will cancel each other out, i.e.
We substitute with
Here we have then
Using the formula of integration,
Other Integral Formulae of the Cotangent Function
The other formulae of cotangent integral with an angle of sine in the form of a function are given as
Example: Evaluate the integral with respect to
We have integral
Using the formula , we have