math.cos() in Python (original) (raw)

Last Updated : 11 Jul, 2025

**math.cos() function in Python is part of the built-in math module, which provides access to mathematical functions. The math.cos() function is used to calculate the cosine of an angle, which is a fundamental trigonometric function widely used in various fields like physics, engineering and computer graphics.

**Example: Cosine Calculation Using math.cos()

Python `

import math

a = math.pi / 6 # angle pi/6 radians

returning the value of cosine of pi / 6

print("The value of cosine of pi / 6 is : ", end="") print(math.cos(a))

`

Output

The value of cosine of pi / 6 is : 0.8660254037844387

**Explanation:

• This code calculates the cosine of the angle pi/6 using Python’s math.cos() function.
• math.cos(a) computes the cosine of the angle a (which is pi/6 radians).

Syntax

math.cos(x)

Parameters

• **x: This parameter represents the angle in radians for which the cosine value is to be calculated.

Return Value

The math.cos() function returns the cosine of the given angle in radians. The value will always be between -1 and 1, inclusive.

Examples of math.cos()

**1. Cosine of Multiple Angles

This example calculates the cosine of several angles ranging from **0 to **2π (full circle) in steps of π/4.

Python `

import math

Angles from 0 to 2π in steps of π/4

angles = [0, math.pi/4, math.pi/2, math.pi, 3math.pi/2, 2math.pi]

Calculate and print the cosine for each angle

for angle in angles: print(f"Cosine of {angle} radians: {math.cos(angle)}")

`

**Output

Cosine of 0 radians: 1.0
Cosine of 0.7853981633974483 radians: 0.7071067811865476
Cosine of 1.5707963267948966 radians: 6.123233995736766e-17
Cosine of 3.141592653589793 radians: -1.0Cosine of 4.71238898038469 radians: -1.8369701987210297e-16
Cosine of 6.283185307179586 radians: 1.0

**Explanation:

• This code calculates the cosine for angles 0, π/4, π/2, π, 3π/2, and 2π.
• It prints the cosine value for each angle.

**2. Graphical Representation of math.cos() Function

Python `

import math import numpy as np import matplotlib.pyplot as plt

Generate angles from -2π to 2π

in_array = np.linspace(-(2 * np.pi), 2 * np.pi, 20) # Generate angles from -2π to 2π

List to store cosine values

out_array = []

for i in range(len(in_array)): out_array.append(math.cos(in_array[i]))

print("in_array : ", in_array) print("\nout_array : ", out_array)

Plot the graph for cosine values

plt.plot(in_array, out_array, color='red', marker="o") plt.title("math.cos()") plt.xlabel("X") plt.ylabel("Y") plt.show()

`

**Output

in_array : [-6.28318531 -5.62179738 -4.96040945 -4.29902153 -3.6376336 -2.97624567
-2.31485774 -1.65346982 -0.99208189 -0.33069396 0.33069396 0.99208189
1.65346982 2.31485774 2.97624567 3.6376336 4.29902153 4.96040945
5.62179738 6.28318531]

out_array : [1.0, 0.7891405093963934, 0.2454854871407988, -0.40169542465296987,
-0.8794737512064891, -0.9863613034027223, 0.6772815716257412,
-0.08257934547233249, 0.5469481581224268, 0.9458172417006346,
0.9458172417006346, 0.5469481581224268, 0.0825793454723316, -0.6772815716257405,
-0.9863613034027223, -0.8794737512064893, -0.40169542465296987,
0.2454854871407988, .7891405093963934, 1.0]