2x2 Matrix Inverse

Problem

Compute the inverse of a 2x2 matrix. If the determinant is 0, return None.

inv(A) = (1/det) * [[A[1][1], -A[0][1]], [-A[1][0], A[0][0]]]

Hint

Swap the diagonal elements, negate the off-diagonal, divide by det.

case 1

in: [[[4,7],[2,6]]]

expected: [[0.6,-0.7],[-0.2,0.4]]

case 2

in: [[[1,2],[3,4]]]

expected: [[-2,1],[1.5,-0.5]]

case 3

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

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

case 4

in: [[[1,2],[2,4]]]

expected: null

Starter codePython

def inverse_2x2(A):
    # Your code here
    pass

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