English

If A = [(–1, 2, 3),(5, 7, 9),(–2, 1, 1)] and B = [(–4, 1, –5),(1, 2, 0),(1, 3, 1)], then verify that (A + B)' = A' + B'

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Question

If A = `[(-1, 2, 3),(5, 7, 9),(-2, 1, 1)]` and B = `[(-4, 1, -5),(1, 2, 0),(1, 3, 1)]`, then verify that (A + B)' = A' + B'

Sum
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Solution

Given, A = `[(-1, 2, 3),(5, 7, 9),(-2, 1, 1)]` and B = `[(-4, 1, -5),(1, 2, 0),(1, 3, 1)]` 

Then, (A + B) = A = `[(-1, 2, 3),(5, 7, 9),(-2, 1, 1)] + [(-4, 1, -5),(1, 2, 0),(1, 3, 1)]`

= `[(-1 -4, 2 + 1, 3 - 5),(5 + 1, 7 + 2, 9 + 0),(-2 + 1, 1 + 3, 1 + 1)]`

= `[(-5, 3, -2),(6, 9, 9),(-1, 4, 2)]`

Now, (A + B)' = `[(-5, 6, -1),(3, 9, 4),(-2, 9, 2)]`   ...(i)

 A' = `[(-1, 5, -2),(2, 7, 1),(3, 9, 1)]` and B' = `[(-4, 1, 1),(1, 2, 3),(-5, 0, 1)]`

Then,  A' + B' = `[(-1, 5, -2),(2, 7, 1),(3, 9, 1)] + [(-4, 1, 1),(1, 2, 3),(-5, 0, 1)]`

= `[(-1 - 4, 5 + 1, -2 + 1), (2 + 1, 7 + 2, 1 + 3), (3 - 5, 9 + 0, 1 + 1)]`

`[(-5, 6, -1),(3, 9, 4),(-2, 9, 2)]`   ...(ii)

Equations (i) and (ii) prove that,

(A + B)' = A' + B'

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Chapter 3: Matrices - EXERCISE 3.3 [Page 66]

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NCERT Mathematics Part 1 and 2 [English] Class 12
Chapter 3 Matrices
EXERCISE 3.3 | Q 2. (i) | Page 66

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