# Cosine Integral Formula

Integration of the cosine function is an important integral formula in integral calculus. This integral belongs to the trigonometric formulae.

The integration of the cosine function is of the form

To prove this formula, consider

Using the derivative formula , 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.

__Other Integral Formulae of the Cosine Function__

The other formulae of cosine integral with an angle of sine in the form of a function are given as

**1. **

**2. **

__Example__**:** Evaluate the integral with respect to

We have integral

Using the formula , we have

__Example__**:** Evaluate the integral with respect to

We have integral

Using the formula , we have