atan2(y, x) returns value of atan(y/x) in radians. The atan2() method returns a numeric value between –
and representing the angle 
of a (x, y) point and positive x-axis.
Syntax :
atan2(y, x)
Parameter :
(y, x) - Both must be a numeric value.
Returns :
Returns atan(y / x), in radians. The double value isfrom polar coordinate (r, theta).
TypeError :
Returns a TypeError if anything other than float is passed.
Code #1 :
# Python3 program to demonstrate # the atan2() method # imports math import math # prints the theta value of # two negative co-ordinates theta1 = math.atan2(-0.9, -0.9) print("atan2(-0.9, -0.9) : ", theta1) # prints the theta value of # two positive co-ordinates theta2 = math.atan2(1.2, 1.5) print("atan2(1.2, 1.5) : ", theta2) # prints the theta value of one # positive and one negative co-ordinates theta3 = math.atan2(1.2, -1.5) print("atan2(1.2, -1.5):", theta3) |
Output :
atan2(-0.5, -0.5): -2.356194490192345 atan2(1.2, 1.5): 0.6747409422235526 atan2(1.2, -1.5): 2.4668517113662407
Code #2 :
# Python3 program to demonstrate the atan() method # imports math import math # list containing x and y coordinates y = [1, 2, 3, 4] x = [6, 3, 7, 8] # traversing in range to get theta # for all y and x co-ordinates for i in range(len(x)): theta = math.atan2(y[i], x[i]) print(theta) |
Output :
0.16514867741462683 0.5880026035475675 0.40489178628508343 0.4636476090008061
Code #3 : Program demonstrating the error
# Python3 program to demonstrate the # TypeError in atan() method # importing math import math y, x = 3, 6 # when integer values are passed # it returns a TypeError theta = math.atan2([y], [x]) print(theta) |
Output :
Traceback (most recent call last):
File "/home/622586ab389561bcdbfff258aca01e65.py", line 9, in
theta = math.atan2([y],[x])
TypeError: a float is required
Practical Application :
This function is used to find the slope in radians when Y and X co-ordinates are given.
Code #4 :
# Let's find the slope when X # and Y co-ordinates are given # imports math import math # X and Y are co-ordinates X = 2; Y = 2 # slope in radians theta1 = math.atan2(Y, X) # print the Slope in radians print(theta1) |
Output :
0.7853981633974483
