**Cotangent**() is a trigonometric ratio. In a right triangle with an angle ,

is the side of the triangle not part of angle , and is the side of the triangle that is part of angle .

## Properties

The reciprocal of cotangent is tangent (abbreviated as ), while its inverse is or . Note that cotangent is not being raised to the power of -1; this is an inverse function, not a reciprocal.

The derivative of is , while its antiderivative is .

It should also be noted that .