How to calculate the cosine of an angle in python ?

Examples of how to get the cosine of an angle in python

Using python math module

To calculate the cosine of an angle in python, a solution is to use the python math module:

import math

angle = 0.7 # angle in radians

math.cos(angle)

returns

0.7648421872844885

Another example

angle = 0. # angle in radians

math.cos(angle)

returns

1.0

Note to get pi number value:

math.pi

returns

3.141592653589793

Example:

angle = math.pi

math.cos(angle)

returns

-1.0

Or

angle = math.pi / 2.0 # angle in radians

math.cos(angle)

returns

6.123233995736766e-17

Convert degrees to radians

If angles are in degrees, it is possible to convert them in radians using math

angle = 90
angle = math.radians(angle)

returns

1.5707963267948966

and

math.cos(angle)

returns

6.123233995736766e-17

Cosine for a list of angles

angles = [0,math.pi/3.0,math.pi/2.0,math.pi]

returns

[0, 1.0471975511965976, 1.5707963267948966, 3.141592653589793]

A solution is to use a list comprehension

[math.cos(angle) for angle in angles]

returns

[1.0, 0.5000000000000001, 6.123233995736766e-17, -1.0]

Cosine for an array of angles

import numpy as np

A = np.array([0, 1.0471975511965976, 1.5707963267948966, 3.141592653589793])

returns

array([0.        , 1.04719755, 1.57079633, 3.14159265])

then

np.cos(A)

returns

array([ 1.000000e+00,  5.000000e-01,  6.123234e-17, -1.000000e+00])