हिंदी

If A = [(cos α, sin α), (–sin α, cos α)], then verify that A' A = I

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प्रश्न

If A = `[(cos α, sin α), (-sin α, cos α)]`, then verify that  A' A = I

योग
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उत्तर

Given, A = `[(cos α, sin α), (-sin α, cos α)]`

So, A' = `[(cos α, -sin α), (sin α, cos α)]`

Now, A' A = `[(cos α, -sin α), (sin α, cos α)] xx [(cos α, sin α), (-sin α, cos α)]`

= `[(cos^2 α + sin^2 α, cos α sin α - sin α cos α),(sin α cos α - cos α sin α, sin^2 + cos^2 α)]`

= `[(1, 0),(0, 1)]` = I   ...[∵ sin2 α + cos2 α = 1]

Hence, A' A = I

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अध्याय 3: Matrices - EXERCISE 3.3 [पृष्ठ ६७]

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एनसीईआरटी Mathematics Part 1 and 2 [English] Class 12
अध्याय 3 Matrices
EXERCISE 3.3 | Q 6. (i) | पृष्ठ ६७

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