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Let M = R{(xxxx):x∈R-{0}} and let * be the matrix multiplication. Determine whether M is closed under *. If so, examine the commutative and associative properties satisfied by * on M - Mathematics

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प्रश्न

Let M = `{{:((x, x),(x, x)) : x ∈ "R"- {0}:}}` and let * be the matrix multiplication. Determine whether M is closed under *. If so, examine the commutative and associative properties satisfied by * on M

बेरीज

उत्तर

Let M = `{{:((x, x),(x, x)) : x ∈ "R"- {0}:}}`

Closure axiom:

Take A = `((x, x),(x, x)) ∈ "M"`

B =  `((y, y),(y, y)) ∈ "M"`

Then AB = `((2xy, 2xy),(2xy, 2xy))`

Since x ≠ 0, y ≠ 0

We see that 2xy ≠ 0 and So AB ∈ M.

This shows that M is closed under matrix multiplication.

Commutative axiom:

AB = `((2xy, 2xy),(2xy, 2xy))`

= BA for all A, B ∈ M

Here, Matrix multiplication is commutative ......(though in general, matrix multiplication is not commutative)

Associative axiom:

Since matrix multiplication is associative, this axiom holds goods for M.

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पाठ 12: Discrete Mathematics - Exercise 12.1 [पृष्ठ २३६]

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सामाचीर कलवी Mathematics - Volume 1 and 2 [English] Class 12 TN Board
पाठ 12 Discrete Mathematics
Exercise 12.1 | Q 9. (i) | पृष्ठ २३६

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