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

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Question

Prove the following identities:

`((cosecA - cotA)^2 + 1)/(secA(cosecA - cotA)) = 2cotA`

Sum

Solution

L.H.S. = `((cosecA - cotA)^2 + 1)/(secA(cosecA - cotA))`

= `(cosec^2A + cot^2A - 2cosecAcotA + 1)/(secA(cosecA - cotA))`

= `(cosec^2A + (1 + cot^2A) - 2cosecAcotA)/(secA(cosecA - cotA))`

= `(cosec^2A + cosec^2A - 2cosecAcotA)/(secA(cosecA - cotA))`

= `(2cosec^2A - 2cosecAcotA)/(secA(cosecA - cotA))`

= `(2cosecA(cosecA - cotA))/(secA(cosecA - cotA))`

= `(2cosecA)/secA`

= `(2 1/sinA)/(1/cosA)`

= `2/sinA xx cosA/1`

= `2 cosA/sinA`

= 2 cot A = R.H.S.

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Chapter 21: Trigonometrical Identities - Exercise 21 (E) [Page 332]

APPEARS IN

Selina Mathematics [English] Class 10 ICSE
Chapter 21 Trigonometrical Identities
Exercise 21 (E) | Q 1.12 | Page 332
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