NTA Abhyas JEE Main2020MathematicsDeterminantsPractice
If A ≠ B , A B = B A and A 2 = B 2 , then the value of the determinant of matrix A + B is (where A and B are square matrices of order 3 × 3 )
Options
- A0
- B1
- C3 3
- D3 2
Correct answer
A. 0
Step-by-step solution
A 2 - B 2 = A - B A + B = 0 given   A B = B A Since, A ≠ B ⇒ A - B is not a null matrix Hence, A + B is a null matrix or d e t A - B = d e t A + B = 0 In both cases d e t A + B = 0