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Using Cofactors of elements of second row, evaluate △=|538201123| - Mathematics

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प्रश्न

Using Cofactors of elements of second row, evaluate `triangle = |(5,3,8),(2,0,1),(1,2, 3)|`

योग

उत्तर

The co-sections of the second row will be like this: 

`A_21 = (-1)^(2 + 1) abs ((3,8),(2,3)) = (-1) xx [3 xx 3 - 2 xx 8] = 7`

`A_22 = (- 1)^(2 + 2) abs ((5,8),(1,3)) = 1 [5 xx 3 - 1 xx 8] = 7`

`A_23 = (-1)^(2 + 3) abs ((5,3),(1,2)) = (-1) [5 xx 2 - 3 xx 1] = - 7`

`therefore Delta = a_21 * A_21 + a_22 * A_22 + a_23 * A_23`

`= 2 xx 7 + 0 xx 7 + 1 xx (- 7)`

`= 14 - 7 = 7`

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अध्याय 4: Determinants - Exercise 4.4 [पृष्ठ १२६]

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एनसीईआरटी Mathematics [English] Class 12
अध्याय 4 Determinants
Exercise 4.4 | Q 3 | पृष्ठ १२६

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