NTA Abhyas JEE Main2020MathematicsMatricesPractice
Let A and B are square matrices of order 3 such that A B 2 = B A and B A 2 = A B . If A B 3 = A 3 B m , then m is equal to
Options
- A3
- B4
- C5
- D7
Correct answer
D. 7
Step-by-step solution
A B 3 = A B A B A B = A B A B A B = A A B 2 A B 2 B = A 2 B B A B 3 = A 2 B A B 2 B 3 = A 2 B A B 5 = A 2 A B 2 B 5 = A 3 B 7