Python - math.acos() function

Last Updated : 28 May, 2020

Math module contains a number of functions which is used for mathematical operations. The math.acos() function returns the arc cosine value of a number. The value passed in this function should be in between -1 to 1.

Syntax: math.acos(x) Parameter:This method accepts only single parameters.

x :This parameter is the value to be passed to acos()

Returns:This function returns the arc cosine value of a number.

Below examples illustrate the use of above function: Example 1:

Python3

# Python code to implement # the acos()function # importing "math" # for mathematical operations  import math a = math.pi / 6 # returning the value of arc cosine of pi / 6  print ("The value of arc cosine of pi / 6 is : ", end ="") print (math.acos(a))

Output:

 The value of arc cosine of pi / 6 is : 1.0197267436954502

Example 2:

Python3

# Python code implementation of  # the acos() function import math import numpy as np import matplotlib.pyplot as plt in_array = np.linspace(-(1 / 3.5 * np.pi), 1 / 3.5 * np.pi, 20) out_array = [] for i in range(len(in_array)): out_array.append(math.acos(in_array[i])) i += 1 print("Input_Array : \n", in_array) print("\nOutput_Array : \n", out_array) plt.plot(in_array, out_array, "go-") plt.title("math.acos()") plt.xlabel("X") plt.ylabel("Y") plt.show()

Output:

 Input_Array : [-0.8975979 -0.80311391 -0.70862992 -0.61414593 -0.51966194 -0.42517795 -0.33069396 -0.23620997 -0.14172598 -0.04724199 0.04724199 0.14172598 0.23620997 0.33069396 0.42517795 0.51966194 0.61414593 0.70862992 0.80311391 0.8975979 ] Output_Array : [2.6850860217724004, 2.50329950258761, 2.358350863035667, 2.2320996324218134, 2.1172515505585388, 2.009954812757658, 1.9078351422171613, 1.809259917693194, 1.7130011090538158, 1.6180559117526183, 1.5235367418371748, 1.4285915445359774, 1.3323327358965993, 1.233757511372632, 1.131637840832135, 1.0243411030312544, 0.9094930211679799, 0.783241790554126, 0.6382931510021833, 0.45650663181739287]