JEE Advanced2012MathematicsMatricesActual
If the adjoint of a 3 3 matrix P is [ array lll 1 & 4 & 4 2 & 1 & 7 1 & 1 & 3 array ] , then the possible value(s) of the determinant of P is (are)
Options
- A-2
- B-1
- C1
- D2
Correct answer
A. -2
Step-by-step solution
We know for a third order matrix P , | Adj P|=|P|² Where aligned &| Adj P|=1(3-7)-4(6-7)+4(2-1)=4 &|P|²=4 P |P|=2 or -2 aligned