If A=(egin{bmatrix}1 & 2\4 & 2end{b | Class 12 Mathematics Chapter Determinants, Determinants NCERT Solutions

Question: If A=\(\begin{bmatrix}1 & 2\\4 & 2\end{bmatrix}\), then show that |2A| = 4|A|
Answer:

The given matrix is

\(u=\begin{bmatrix}1 & 2\\4 & 2\end{bmatrix}\) 

 

So 2A = 2\(\begin{bmatrix}1 & 2\\4 & 2\end{bmatrix}\)

 

          \(= \begin{bmatrix}2 & 4\\8 & 4\end{bmatrix}\)

 

so L.H.S. = |2A| \(= \begin{bmatrix}2 & 4\\8 & 4\end{bmatrix}\)

                 = 2 x 4 - 4 x 8

                = 8 - 32

                 = -24

 

Now, |A| \(= \begin{bmatrix}1 & 2\\4 & 2\end{bmatrix}\)  
= 1 x 2 - 2 x 4
= 2 - 8
= -6
 
So R.H.S. = 4 |A| = 4 x (-6) = -24
 
So L.H.S. = R.H.S.
 


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Comments

  • Sanket
  • 2018-11-24 15:51:45

Plzz give all difficult question.


Comment(s) on this Question

Welcome to the NCERT Solutions for Class 12 Mathematics - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 3: If A=(egin{bmatrix}1 & 2\4 & 2end{bmatrix}), then show that |2A| = 4|A|....