Question

Write a python function (Without using external libraries) to calculate the 1). determinate of a 2 x 2 matrix 2). Calculate the inverse of a 2 x 2 matrix.

Answer 1

matrix1=[]
for i in range(0,2):                            # Loops for rows
    element =[]                                 # Creating an empty list for each row
    for j in range(0,2):                        # Loops for columns 
         element.append(int(input()))           # Takes input from user and appends to matrix1
    matrix1.append(element)                     # Appending the scanned element to matrix indexes
Determinant=matrix1[0][0]*matrix1[1][1] - matrix1[0][1]*matrix1[1][0]   # Finding the determinant 
print("Determinant is {}".format(Determinant))            # Prints the determinant

matrix_inv=[[],[]]                              # Creates the empty list of list for rows and columns
store=1/Determinant                             # Stores the inverse of determinant

if(Determinant==0):
    print("Inverse doesnot exist")
else:
    matrix_inv[0].append(matrix1[1][1]*store)   # Does inverse operation for the 1x1 positions
    matrix_inv[0].append(-(matrix1[0][1]*store))# Does inverse operation for the 0x1 positions
    matrix_inv[1].append(-(matrix1[1][0]*store))# Does inverse operation for the 1x0 positions
    matrix_inv[1].append(matrix1[0][0]*store)   # Does inverse operation for the 0x0 positions

print("Inverse of a matrix is {}".format(matrix_inv))   # Prints the inverse of matrix