Angle from Rotation Matrix

Problem

Recover the rotation angle in degrees from a 2D rotation matrix R:

theta = degrees(atan2(R[1][0], R[0][0]))

The result lies between -180 and 180 degrees.

Hint

atan2 uses the sign of both components, so it distinguishes clockwise from counterclockwise.

case 1

in: [[[1,0],[0,1]]]

expected: 0

case 2

in: [[[0,-1],[1,0]]]

expected: 90

case 3

in: [[[-1,0],[0,-1]]]

expected: 180

case 4

in: [[[0.7071067811865476,0.7071067811865476],[-0.7071067811865476,0.7071067811865476]]]

expected: -45

Starter codePython

def rotation_angle(R):
    # Your code here
    pass

4 test cases · run your code against them in the editor