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If A and B are square matrices of the same order, then (AB)′ = ______. - Mathematics

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प्रश्न

If A and B are square matrices of the same order, then (AB)′ = ______.

रिक्त स्थान भरें

उत्तर

If A and B are square matrices of the same order, then (AB)′ = B'A'.

Explanation:

Let A = [aij]m × n and B = [bij]n × p be two martices.

Then, AB is an m × p matrix.

Therefore (AB)' is a p × m matrix.

Since A' and B' are n × m and p ×n matrices.

Therefore B'A' is a p × m matrix.

Thus, the two matrices (AB)' and B'A' are of the same order such that ((AB)')ij = (AB)ij

= `sum_("r" = 1)^"n" "a"_"jr""b"_"ri"`

= `sum_("r" = 1)^"n" "b"_"ri""a"_"jr"`

= `sum_("r" = 1)^"n" ("B'")_"ir"("A'")_"rj"`

= `("B'A'")_"ij"`

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अध्याय 3: Matrices - Exercise [पृष्ठ ६३]

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एनसीईआरटी एक्झांप्लर Mathematics [English] Class 12
अध्याय 3 Matrices
Exercise | Q 76.(i) | पृष्ठ ६३

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