Reflection Matrix across Line

Problem

Build the 2x2 matrix that reflects across the line through the origin at angle theta degrees:

R = [[cos(2t), sin(2t)], [sin(2t), -cos(2t)]]

with t = radians(theta).

Hint

A reflection matrix is symmetric with determinant -1 and has the line as its +1 eigenspace.

case 1

in: [0]

expected: [[1,0],[0,-1]]

case 2

in: [90]

expected: [[-1,0],[0,1]]

case 3

in: [45]

expected: [[0,1],[1,0]]

case 4

in: [30]

expected: [[0.5,0.8660254037844386],[0.8660254037844386,-0.5]]

Starter codePython

def reflection_matrix_2d(theta_degrees):
    # Your code here
    pass

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