# cmath – mathematical functions for complex numbers

This module implements a subset of the corresponding CPython module, as described below. For more information, please refer to the original CPython documentation: cmath.

The `cmath` module provides some basic mathematical functions for dealing with complex numbers.

## Function

### cos

``````cmath.cos(z)
``````

Returns the cosine of `z`.

### exp

``````cmath.exp(z)
``````

Returns the exponent of `z`.

### log

``````cmath.log(z)
``````

Returns the natural logarithm of `z`. The branch cuts along the negative real axis.

### log10

``````cmath.log10(z)
``````

Returns the base 10 logarithm of `z`. The branch cuts along the negative real axis.

### phase

``````cmath.phase(z)
``````

Returns the phase, range (-pi, +pi) of the number "z".

### polar

``````cmath.polar(z)
``````

Return the polar form of `z` as a tuple.

### rect

``````cmath.rect(r, phi)
``````

Returns the complex number of the modulus `r` and the phase `phi`.

### sin

``````cmath.sin(z)
``````

Returns the sine of `z`.

### sqrt

``````cmath.sqrt(z)
``````

Returns the square root of `z`.

## Constants

### cmath.e

The basis of natural logarithm

### cmath.pi

Ratio of circumference to diameter