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Find the inverse of the matrices (if it exists). [2-243] - Mathematics

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प्रश्न

Find the inverse of the matrices (if it exists).

`[(2,-2),(4,3)]`

योग
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उत्तर

Let A = `[(2,-2),(4,3)]`

Then, |A| = `|(2,-2),(4,3)|`

= 6 + 8

= 14 ≠ 0

So, A is a non-singular matrix and therefore it is invertible. Let Cij be the cofactor of aij in A.

Then, the cofactors of elements of A are given by,

C11 = (−1)1+1 (3) = 3

C12 = (−1)1+2 (4) = (−4)

C21 = (−1)2+1 (−2) = 2

C22 = (−1)2+2 (2) = 2

∴ Adj A = `[(3,-4),(2,2)]^' = [(3,2),(-4,2)]`

Hence, A−1 = `1/|A| ("Adj A")`

= `1/14 [(3,2),(-4,2)]`

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अध्याय 4: Determinants - Exercise 4.5 [पृष्ठ १३२]

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एनसीईआरटी Mathematics Part 1 and 2 [English] Class 12
अध्याय 4 Determinants
Exercise 4.5 | Q 5 | पृष्ठ १३२

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