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If A = [01231-1] and B = [121210], then find (AB)−1 - Mathematics and Statistics

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प्रश्न

If A = `[(0, 1),(2, 3),(1, -1)]` and B = `[(1, 2, 1),(2, 1, 0)]`, then find (AB)−1 

योग

उत्तर

AB = `[(0, 1),(2,3),(1, -1)] [(1, 2, 1),(2, 1, 0)]`

= `[(0 + 2, 0 +1, 0 + 0),(2 + 6, 4 + 3, 2 + 0),(1 - 2, 2 - 1, 1 + 0)]`

= `[(2, 1, 0),(8, 7, 2),(-1, 1, 1)]`

∴ |AB| = `2|(7, 2),(1, 1)| -1|(8, 2),(-1, 1)| + 0`

= 2(7 – 2) – (8 + 2)

= 10 – 10

= 0

∴  (AB)−1 does not exist.

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