1.

Let `A` and `B` be two non-singular square matrices such that `B ne I` and `AB^(2)=BA`. If `A^(3)-B^(-1)A^(3)B^(n)`, then value of `n` isA. `4`B. `5`C. `8`D. `7`

Answer» Correct Answer - C
`(c )` `BA=AB^(2)`
`impliesBA=AB^(2)`
`impliesA=B^(-1)AB^(2)`
`impliesA^(2)=(B^(-1)AB^(2))(B^(-1)AB^(2))`
`=B^(-1)A(BA)B^(2)`
`impliesB^(-1)A AB^(2)B^(2)`
`=B^(-1)A^(2)B^(4)`
`:.A^(3)=B^(-1)A^(3)B^(6)`


Discussion

No Comment Found

Related InterviewSolutions