MHT CET202019 Oct 2020Morning ShiftMathematicsMatricesActual
If is a complex cube root of unity and A= [ array cc & 0 0 & array ] , then A⁻¹=
Options
- AA ²
- B2 ~A
- C- A
- DA
Correct answer
A. A ²
Step-by-step solution
(C) Given A= [ array ll & 0 0 & array ] |A|= ( ²-0 )= ² and adj A= [ array cc & 0 0 & array ] A⁻¹= 1 ² [ array ll & 0 0 & array ]= [ array cc 1 & 0 0 & 1 array ]= [ array cc ² & 0 0 & ² array ] [ ³=1 ] A²= [ array ll & 0 0 & array ] [ array ll & 0 0 & array ]= [ array cc ² & 0 0 & ² array ]