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Find the inverse of the matrices (if it exists). [(1,2,3),(0,2,4),(0,0,5)] - Mathematics

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प्रश्न

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

`[(1,2,3),(0,2,4),(0,0,5)]`

बेरीज
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उत्तर

Let A = `[(1,2,3),(0,2,4),(0,0,5)]`

|A| = `|(1,2,3),(0,2,4),(0,0,5)|`

= 1(10 − 0) − 2(0 − 0) + 3(0 − 0)

= 10 ≠ 0

Now for cofactor Cij = (−1)i+j Mij

C11 = `(-1)^(1+1) |(2,4), (0,5)|` = 10

C12 = `(-1)^(1+2) |(0,4), (0,5)|` = 0

C13 = `(-1)^(1+3)|(0,2),(0,0)|` = 0

C21 = `(-1)^(2+1) |(2,3), (0,5)|` = −10

C22 = `(-1)^(2+2) |(1,3), (0,5)|` = 5

C23 = `(-1)^(2+3) |(1,2), (0,0)|` = 0

C31 = `(-1)^(3+1) |(2,3), (2,4)|` = 2

C32 = `(-1)^(3+2) |(1,3), (0,4)|` = −4

C33 = `(-1)^(3+3)|(1,2), (0,2)|` = 2

∴ Adj A = `[(10,0,0),(-10,5,0),(2,-4,2)]^' = [(10,-10,2),(0,5,-4),(0,0,2)]`

Hence, A−1 = `1/|A|` Adj A

= `1/10 [(10,-10,2),(0,5,-4),(0,0,2)]`

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पाठ 4: Determinants - Exercise 4.5 [पृष्ठ १३२]

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एनसीईआरटी Mathematics Part 1 and 2 [English] Class 12
पाठ 4 Determinants
Exercise 4.5 | Q 7 | पृष्ठ १३२

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