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Prove the Following Identity : ( Cot a − Cos E C a ) 2 = 1 − Cos a 1 + Cos a - Mathematics

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Question

Prove the following identity : 

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

Sum

Solution

LHS = `(cotA - cosecA)^2`

 = `[cosA/sinA - 1/sinA]^2`

= `[(cosA - 1)/sinA]^2`

= `(cosA - 1)^2/sin^2A = (cosA - 1)^2/(1 - cos^2A)`

= `(-(1 - cosA))^2/((1 - cosA)(1 + cosA)) = ((1 - cosA)(1 - cosA))/((1 - cosA)(1 + cosA))`

= `(1 - cosA)/(1 + cosA)`

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Chapter 21: Trigonometric Identities - Exercise 21.1

APPEARS IN

Frank Mathematics - Part 2 [English] Class 10 ICSE
Chapter 21 Trigonometric Identities
Exercise 21.1 | Q 3.1
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