# cmath – mathematical functions for complex numbers

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

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

Availability: not available on WiPy and ESP8266. Floating point support required for this module.

## 1. Functions

### 1.1. cos

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

Return the cosine of `z`.

### 1.2. exp

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

Return the exponential of `z`.

### 1.3. log

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

Return the natural logarithm of `z`. The branch cut is along the negative real axis.

### 1.4. log10

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

Return the base-10 logarithm of `z`. The branch cut is along the negative real axis.

### 1.5. phase

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

Returns the phase of the number `z`, in the range (-pi, +pi].

### 1.6. polar

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

Returns, as a tuple, the polar form of `z`.

### 1.7. rect

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

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

### 1.8. sin

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

Return the sine of `z`.

### 1.9. sqrt

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

Return the square-root of `z`.

## 2. Constants

### 2.1. cmath.e

base of the natural logarithm

### 2.2. cmath.pi

the ratio of a circle’s circumference to its diameter