मराठी

If x, y, z are nonzero real numbers, then the inverse of matrix A = [(x,0,0),(0,y,0),(0,0,z)] is ______. - Mathematics

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प्रश्न

If x, y, z are nonzero real numbers, then the inverse of matrix A = `[(x,0,0),(0,y,0),(0,0,z)]` is ______.

पर्याय

  • `[(x^(-1),0,0),(0, y^(-1),0),(0,0,z^(-1))]`

  • `xyz[(x^(-1),0,0),(0,y^(-1),0),(0,0,z^(-1))]`

  • `1/(xyz)[(x,0,0),(0,y,0),(0,0,z)]`

  • `1/(xyz)[(1,0,0),(0,1,0),(0,0,1)]`

MCQ
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उत्तर

If x, y, z are nonzero real numbers, then the inverse of matrix A = `[(x,0,0),(0,y,0),(0,0,z)]` is `underlinebb([(x^(-1),0,0),(0, y^(-1),0),(0,0,z^(-1))])`.

Explanation:

Let, A = `[(x,0,0),(0,y,0),(0,0,z)]`

∴ |A| = x[yz − 0] = xyz

∴ A11 = `(-1)^(1 + 1)[(y,0),(0,z)]`

= (−1)2 [yz − 0]

= 1 × yz

= yz

A12 = `(-1)^(1 + 2)[(0,0),(0,z)]`

= (−1)3 [0 − 0]

= 0

A13 = `(-1)^(1 + 3)[(0,y),(0,0)]`

= (−1)4 [0 − 0]

= 0

A21 = `(-1)^(2 + 1)[(0,0),(0,z)]`

= (−1)3 [0 − 0]

= 0

A22 = `(-1)^(2 + 2)[(x,0),(0,z)]`

= (−1)4 [xz − 0]

= 1 × zx

= zx

A23 = `(-1)^(2 + 3)[(x,0),(0,0)]`

= (−1)5 [0 − 0]

= 0

A31 = `(-1)^(3 + 1)[(0,0),(0,z)]`

= (−1)4 [0 − 0]

= 0

A32 = `(-1)^(3 + 2)[(x,0),(0,0)]`

= (−1)5 [0 − 0]

= 0

A33 = `(-1)^(3 + 3)[(x,0),(0,y)]`

= (−1)6 [xy − 0]

= xy

∴ adj A = `[(yz,0,0),(0,zx,0),(0,0,xy)] = [(yz,0,0),(0,zx,0),(0,0,xy)]`

A−1 = `1/|A|` (adj A)

= `1/(xyz)[(yz,0,0),(0,zx,0),(0,0,xy)]`

= `[(1/x,0,0),(0,1/y,0),(0,0,1/z)]`

= `[(x^-1,0,0),(0,y^-1,0),(0,0,z^-1)]`

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पाठ 4: Determinants - Exercise 4.7 [पृष्ठ १४३]

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एनसीईआरटी Mathematics Part 1 and 2 [English] Class 12
पाठ 4 Determinants
Exercise 4.7 | Q 18 | पृष्ठ १४३

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