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Evaluate: cos(sin-1(45)+sin-1(1213)) - Business Mathematics and Statistics

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प्रश्न

Evaluate: `cos (sin^-1 (4/5) + sin^-1 (12/13))`

योग

उत्तर

`sqrt(5^2 - 4^2)` = 3

cos A = `"Adj"/"Hyp" = 3/5`

Let `sin^-1 (4/5)` = A

sin A = `4/5`

∴ cos A = `3/5`

`sqrt(169 - 144) = sqrt 25` = 5

cos B = `"Adj"/"Hyp" = 5/13`

Let `sin^-1 (12/13)` = B

`12/13` = sin B

sin B = `12/13`

∴ cos B = `5/13`

Now `cos (sin^-1 (4/5) + sin^-1 (12/13))` = cos (A + B)

= cos A cos B – sin A sin B

`= 3/5 xx 5/13 - 4/5 xx 12/13`

`= 15/65 - 48/65`

`= - 33/65`

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  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 4: Trigonometry - Exercise 4.4 [पृष्ठ ९२]

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सामाचीर कलवी Business Mathematics and Statistics [English] Class 11 TN Board
अध्याय 4 Trigonometry
Exercise 4.4 | Q 7 | पृष्ठ ९२
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