99 Percentile Qs Bank for JEE MainMathematicsMatrices
Let A , B , C , D be square real matrices such that C T = D A B ,   D T = A B C ,   S = A B C D , then S 2 is equal to
Options
- AS
- BB C D
- CS T
- DS T 2 = S 2 T
Correct answer
D. S T 2 = S 2 T
Step-by-step solution
Given C T = D A B ,   D T = A B C ,   S = A B C D Using S T = A B C D T = D T C T B T A T , We get S T 2 = D T C T B T A T 2 = D T C T B T A T D T C T B T A T = D T C T D A B T A B C T = D T C T C D And, S 2 T = A B C ⏟ D A B ⏟ C D T = D T C T C D Hence, S T 2 = S 2 T