numpy.arccos(x[, out]) = ufunc ‘arccos’) : This mathematical function helps user to calculate inverse cos for all x(being the array elements).
Parameters :
array : [array_like]elements are in radians. out : [array_like]array of same shape as x.
Note :
2pi Radians = 360 degrees
The convention is to return the angle z whose real part lies in [0, pi].
Return :
An array with inverse cosine of x for all x i.e. array elements. The values are in the closed interval [-pi/2, pi/2].
Code #1 : Working
# Python program explaining # arccos() function import numpy as np in_array = [0, 1, 0.3, -1] print ("Input array : \n", in_array) arccos_Values = np.arccos(in_array) print ("\nInverse Cosine values : \n", arccos_Values) |
Output :
Input array : [0, 1, 0.3, -1] Inverse Cosine values : [ 1.57079633 0. 1.26610367 3.14159265]
Code #2 : Graphical representation
# Python program showing # Graphical representation # of arccos() function import numpy as np import matplotlib.pyplot as plt in_array = np.linspace(-np.pi, np.pi, 12) out_array1 = np.cos(in_array) out_array2 = np.arccos(in_array) print("in_array : ", in_array) print("\nout_array with cos : ", out_array1) print("\nout_arraywith arccos : ", out_array1) # red for numpy.arccos() plt.plot(in_array, out_array1, color = 'blue', marker = "*") plt.plot(in_array, out_array2, color = 'red', marker = "o") plt.title("blue : numpy.cos() \nred : numpy.arccos()") plt.xlabel("X") plt.ylabel("Y") plt.show() |
Output :
in_array : [-3.14159265 -2.57039399 -1.99919533 -1.42799666 -0.856798 -0.28559933 0.28559933 0.856798 1.42799666 1.99919533 2.57039399 3.14159265] out_array with cos : [-1. -0.84125353 -0.41541501 0.14231484 0.65486073 0.95949297 0.95949297 0.65486073 0.14231484 -0.41541501 -0.84125353 -1. ] out_arraywith arccos : [-1. -0.84125353 -0.41541501 0.14231484 0.65486073 0.95949297 0.95949297 0.65486073 0.14231484 -0.41541501 -0.84125353 -1. ] RuntimeWarning: invalid value encountered in arccos out_array1 = np.sin(in_array)
References :
https://docs.scipy.org/doc/numpy-dev/reference/generated/numpy.arcsin.html#numpy.arccos
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