मराठी

If A= `[[3 1],[-1 2]]` And I= `[[1 0],[0 1]]`,Then Find λ So That A2 = 5a + λI. - Mathematics

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प्रश्न

\[A = \begin{bmatrix}3 & 1 \\ - 1 & 2\end{bmatrix} and \text{ I} = \begin{bmatrix}1 & 0 \\ 0 & 1\end{bmatrix}\]

बेरीज

उत्तर

Given : `A =[[3     1],[-1      2]]`

Now, 

`A^2`=AA

`⇒A^2= [[3      1],[-1      2]] [[3         1],[-1        2]]`

`⇒A^2=[[9-1                      3+2],[-3-2      -1+4]]`

`⇒A^2=[[8            5],[-5        3]]`

`A^2=5A+λI`

⇒`[[8         5],[-5       3]]=5[[3        1],[-1        2]]+λ[[1      0],[0        1]]`

⇒`[[8         5],[-5       3]]` =`[[15        5],[-5        10]]+[[λ     0],[0       λ]]`

⇒`[[8         5],[-5       3]]`=`[[15+λ      5+0],[-5+0         10+λ]]`

⇒`[[8         5],[-5       3]]``[[15+λ      5+0],[-5+0         10+λ]]`

The corresponding elements of two equal matrices are equal.

∴ 8=15+λ    

⇒8−15=λ 

⇒−7=λ

∴ λ=−7

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पाठ 5: Algebra of Matrices - Exercise 5.3 [पृष्ठ ४३]

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आरडी शर्मा Mathematics [English] Class 12
पाठ 5 Algebra of Matrices
Exercise 5.3 | Q 28 | पृष्ठ ४३

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