First slide

Applications of determinant

Question

Let A be a 3x3 matrix such that $\det (A) = - 2$ . Then $\det (- 2 A^{- 1})$ is equal to

Moderate

A

4
B

-4
C

8
D

-2

Solution

As $A^{- 1}$ is a 3x3 matrix,
$\begin{array}{l} \det (- 2 A^{- 1}) = (- 2)^{3} \det (A^{- 1}) \\ = (- 2)^{3} (\det (A))^{- 1} \\ = (- 8) (- \frac{1}{2}) = 4 \end{array}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App