Skip to content
Related Articles

Related Articles

numpy.arctan() in Python
  • Last Updated : 29 Nov, 2018

numpy.arctan(x[, out]) = ufunc ‘arctan’) : This mathematical function helps user to calculate inverse tangent 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 [-pi/2, pi/2].

Return :



An array with inverse tangent 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
# arctan() function
  
import numpy as np
  
in_array = [0, 1, 0.3, -1]
print ("Input array : \n", in_array)
  
arctan_Values = np.arctan(in_array)
print ("\nInverse Tangent values : \n",
                            arctan_Values)


Output :

Input array : 
 [0, 1, 0.3, -1]

Inverse Tangent values : 
 [ 0.          0.78539816  0.29145679 -0.78539816]

 
Code #2 : Graphical representation




# Python program showing
# Graphical representation  
# of arctan() function
  
import numpy as np
import matplotlib.pyplot as plt
  
in_array = np.linspace(-np.pi, np.pi, 12)
out_array1 = np.tan(in_array)
out_array2 = np.arctan(in_array)
  
print("in_array : ", in_array)
print("\nout_array with tan : ", out_array1)
print("\nout_arraywith arctan : ", 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.tan() \nred : numpy.arctan()")
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 tan :  [  1.22464680e-16   6.42660977e-01   2.18969456e+00  -6.95515277e+00
  -1.15406152e+00  -2.93626493e-01   2.93626493e-01   1.15406152e+00
   6.95515277e+00  -2.18969456e+00  -6.42660977e-01  -1.22464680e-16]

out_arraywith arctan :  [  1.22464680e-16   6.42660977e-01   2.18969456e+00  -6.95515277e+00
  -1.15406152e+00  -2.93626493e-01   2.93626493e-01   1.15406152e+00
   6.95515277e+00  -2.18969456e+00  -6.42660977e-01  -1.22464680e-16]


References :
https://docs.scipy.org/doc/numpy-dev/reference/generated/numpy.arcsin.html#numpy.arccos
.

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course.

My Personal Notes arrow_drop_up
Recommended Articles
Page :