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Prove the following identities: 1+sinAcosecA-cotA-1-sinAcosecA+cotA=2(1+cotA) - Mathematics

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Question

Prove the following identities:

`(1+ sin A)/(cosec A - cot A) - (1 - sin A)/(cosec A + cot A) = 2(1 + cot A)`

Sum

Solution

L.H.S. = `(1 + sin A)/(cosec A - cot A) - (1 - sin A)/(cosec A + cot A)`

= `((1 + sin A)(cosec A + cot A) - (1 - sin A)(cosec A - cot A))/((cosec A - cot A)(cosec A + cot A))`

= `(cosec A + cot A + sin A cosec A + sin A cot A - cosec A + cot A + sin A cosec A - sin A cos A)/(cosec^2A - cot^2A)`

= 2 cot A + 2 sin A cosec A

= 2 cot A + 2 `1/(cosec A) xx cosec A`

= 2 (cot A + 1)

Hence proved.

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Chapter 21: Trigonometrical Identities - Exercise 21 (A) [Page 325]

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Selina Mathematics [English] Class 10 ICSE
Chapter 21 Trigonometrical Identities
Exercise 21 (A) | Q 47 | Page 325
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