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Find the inverse of the matrices (if it exists). [1000cosαsinα0sinα-cosα] - Mathematics

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प्रश्न

Find the inverse of the matrices (if it exists).

`[(1,0,0),(0, cos alpha, sin alpha),(0, sin alpha, -cos alpha)]`

बेरीज

उत्तर

A = `[(1,0,0),(0,cos alpha, sin alpha),(0,sin alpha, -cos alpha)]`

So, adj `A = [(A_11,A_21,A_31),(A_12,A_22,A_32),(A_13,A_23,A_33)]`

`= [(1,0,0),(0,-cos alpha,-sin alpha),(0,-sin alpha,cos alpha)]`

`abs A = 1(- cos^2 alpha = sin alpha) + 0 (0 - 0) + 0 (0 - 0)`

`= -1 ne 0 -> A^-1` exists

`A^-1 = 1/abs A (adj A) = 1/abs A [(A_11,A_21,A_31),(A_12,A_22,A_32),(A_13,A_23,A_33)]`

`1/-1 [(1,0,0),(0,-cos alpha,-sin alpha),(0,-sin alpha,cos alpha)]`

`= [(-1,0,0),(0,cos alpha,sin alpha),(0,sin alpha,-cos alpha)]`

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पाठ 4: Determinants - Exercise 4.5 [पृष्ठ १३२]

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एनसीईआरटी Mathematics [English] Class 12
पाठ 4 Determinants
Exercise 4.5 | Q 11 | पृष्ठ १३२

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