# Python - How To Calculate the Inverse Tangent in Python

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In Python, one can perform many kinds of tasks, including mathematical operations like add, subtract, divide, and deal with matrices. Besides all these operations, you can also perform complex mathematical functions like trigonometric operations using many libraries and modules provided by Python.

This tutorial will show you methods of how to calculate the inverse tangent in Python.

## Use the `arctan()` Function From the `NumPy` Library to Calculate the Inverse Tangent in Python

The `NumPy` library is widely used in Python. It helps you deal with arrays, matrices, linear algebra, and Fourier transforms. Additionally, the term `NumPy` stands for `Numerical Python`.

The `NumPy` library includes an operation known as the `arctan()` function, which is a mathematical function used to calculate the inverse tangent of elements in an array.

Example:

``import numpy as np    array = [-1, 0, 0.5, 1] print ("Array: ", array)    Inv_Tan = np.arctan(array) print("Inverse Tangent values of elements in the given Array : ", Inv_Tan) ``

Output:

``Array:  [-1, 0, 0.5, 1] Inverse Tangent values of elements in the given Array :  [-0.78539816  0.          0.46364761  0.78539816] ``

This function calculates the inverse tangent values of every element present in the input array.

## Use the `atan()` Function From the `SymPy` Library to Calculate the Inverse Tangent in Python

The `SymPy` library of Python is an open-source library of Python used for symbolic mathematics and computer algebra.

The `atan()` function of the `SymPy` library is used for calculating the inverse tangent value of a given input value in Python. Check the example code below.

``from sympy import *  inv_tan1 = atan(0) inv_tan2 = atan(0.5)    print(inv_tan1) print(inv_tan2) ``

Output:

``0 0.463647609000806 ``

## Use the `atan()` Function From the `Math` Library to Calculate the Inverse Tangent in Python

Python’s `Math` library helps in performing complex mathematical problems by providing different mathematical constants and functions in Python.

The `atan()` function of the `Math` library is also used for calculating the inverse tangent value (between -PI/2 and PI/2) of a given input value in Python.

Example:

``import math  print (math.atan(0)) print (math.atan(0.5)) ``

Output:

``0.0 0.46364760900080615 ``