# What is the derivative of cos x?

The derivative of a function characterizes the rate of change of the function at some point. The process of finding the derivative is called differentiation.

## Answer: The derivative of cos x is -sin x.

Let's understand how we arrived at the solution.

**Explanation:**

Let,

y = cos x

Differentiating w.r.t x

dy/dx = [d/dx(cos x)]

dy/dx = -sin x

Also, we can check out the online derivative calculator to verify our answer.