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If possible, using elementary row transformations, find the inverse of the following matrices [20-1510013] - Mathematics

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प्रश्न

If possible, using elementary row transformations, find the inverse of the following matrices

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

बेरीज
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उत्तर

Here, A = `[(2, 0, -1),(5, 1, 0),(0, 1, 3)]`

Put A = IA

`[(2, 0, -1),(5, 1, 0),(0, 1, 3)] = [(1, 0, 0),(0, 1, 0),(0, 0, 1)]"A"`

R1 → 3R1 – R2

`[(1, -1, -3),(5, 1, 0),(0, 1, 3)] = [(3, -1, 0),(0, 1, 0),(0, 0, 1)]"A"`

R2 → R2 – 5R

`[(1, -1, -3),(0, 6, 15),(0, 1, 3)] = [(3, -1, 0),(-15, 6, 0),(0, 0, 1)]"A"`

R2 → R2 – 5R

`[(1, -1, -3),(0, 1, 0),(0, 1, 3)] = [(3, -1, 0),(-15, 6, -5),(0, 0, 1)]"A"`

R3 → R3 – R2  

`[(1, -1, -3),(0, 1, 0),(0, 0, 3)] = [(3, -1, 0),(-15, 6, -5),(15, -6, 6)]"A"`

R1 → R1 + R2  

`[(1, 0, -3),(0, 1, 0),(0, 0, 3)] = [(-12, 5, -5),(-15, 6, -5),(15, -6, 6)]"A"`

`"R"_3 -> 1/3 "R"_3`

`[(1, 0, -3),(0, 1, 0),(0, 0, 1)] = [(-12, 5, -5),(-15, 6, -5),(5, -2, 2)]"A"`

R1 → R1 + 3R3  

`[(1, 0, 0),(0, 1, 0),(0, 0, 1)] = [(3, -1, 1),(-15, 6, -5),(5, -2, 2)]"A"`

Hence, `"A"^-1 = [(3, -1, 1),(-15, 6, -5),(5, -2, 2)]`

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पाठ 3: Matrices - Exercise [पृष्ठ ५९]

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एनसीईआरटी एक्झांप्लर Mathematics [English] Class 12
पाठ 3 Matrices
Exercise | Q 51.(iii) | पृष्ठ ५९

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