.arccos()

In NumPy, the .arccos() function calculates the inverse cosine (arccosine), of each element in an array. The elements in the array should be cosine values, which must lie within the range [-1, 1]. The function returns the corresponding angle in radians for each cosine value.

Syntax

numpy.arccos(array, out = None, where=True)

• array: An array-like or scalar containing cosine values. The function computes the inverse cosine of each element.
• out: An optional parameter specifying an array where the result will be stored. If not provided, a new array is created.
• where: A condition or boolean array that determines which elements of array are used to compute the inverse cosine. The inverse cosine is computed only for elements where the condition is True; other elements remain unchanged.

Example

In the example below, the .arccos() function calculates the inverse cosine of each element in a NumPy array and prints the resulting angles in radians:

import numpy as np

# Array of cosine values within the range [-1, 1]
cos_values = np.array([1, 0, -1])

# Compute the arccosine of each element
angles_in_radians = np.arccos(cos_values)

# Returned values are in radians
print("Arccosine:", angles_in_radians)

The output would be:

Arccosine:  [0.         1.57079633 3.14159265]

Note: The function returns NaN for values outside the range [-1, 1], since the arccosine is not defined for those values.

Codebyte Example

Run the following code to understand how the .arccos() function works:

us
Visit us
code
Hide code
Code
Output
Hide output
Hide output
Loading...
Run