Both E1 and E2 are from problem 1 State at least one reason

Both E_1 and E_2 are from problem 1. State at least one reason why both E_1 and E_2 are invertible matrices. Find both E^-1_1 and E^-1_2 and show that E^-1E_1 = I, E^-1_2 E_2=I, where I is the 3 times 3 identity matrix.

Solution

a)since i dont have matrix, follow simple steps

calculate determiniant of matrices E1 and E2. if its zero then it is not invertible. if its non zero, it can be inverted.

b) find out E1 and E2 inverse using cofactors.. then multiply them with E1 and E2 respectivly. you will find out product is identity matrix.