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If A = [3-41120] and B = [212124], then verify (BA)2 ≠ B2A2 - Mathematics

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प्रश्न

If A = `[(3, -4),(1, 1),(2, 0)]` and B = `[(2, 1, 2),(1, 2, 4)]`, then verify (BA)2 ≠ B2A2 

योग

उत्तर

Here, B = `[(2, 1, 2),(1, 2, 4)]_(2 xx 3)` and A = `[(3, -4),(1, 1),(2, 0)]_(3 xx 2)`

∴ BA = `[(6 + 1 + 4, -8 + 1 + 0),(3 + 2 + 8, -4 + 2 + 0)]_(2 xx 2)`

⇒ BA =  `[(11, -7),(13, -2)]`

L.H.S. (BA)2 = (BA) · (BA)

= `[(11, -7),(13, -2)][(11, -7),(13, -2)]`

⇒ `[(121 - 91, -77 + 14),(143 - 26, -91 + 4)]`

⇒ `[(30, -63),(117, -87)]`

R.H.S B2 = B · B

= `[(2, 1, 2),(1, 2, 4)]_(2 xx 3) * [(2, 1, 2),(1, 2, 4)]_(2 xx 3)`

Here, number of columns of first

i.e., 3 is not equal to the number of rows of second matrix i.e., 2.

So, B2 is not possible.

Similarly, A2 is also not possible.

Hence, (BA)2 · B2A2 

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अध्याय 3: Matrices - Exercise [पृष्ठ ५४]

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एनसीईआरटी एक्झांप्लर Mathematics [English] Class 12
अध्याय 3 Matrices
Exercise | Q 14 | पृष्ठ ५४

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