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` (Sin Theta + Cos Theta )/(Sin Theta - Cos Theta ) + ( Sin Theta - Cos Theta )/( Sin Theta + Cos Theta) = 2/ ((1- 2 Cos^2 Theta))` - Mathematics

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Question

` (sin theta + cos theta )/(sin theta - cos theta ) + ( sin theta - cos theta )/( sin theta + cos theta) = 2/ ((1- 2 cos^2 theta))`

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Solution

LHS =  `(sin theta + cos theta )/(sin theta - cos theta ) + ( sin theta - cos theta )/( sin theta + cos theta)`

      =` ((sin theta + cos theta )^2 + ( sin theta - cos theta)^2)/(( sin theta - cos theta ) ( sin theta + cos theta))`

      =`( sin^2 theta + cos^2 theta + 2 sin theta   cos theta + sin^2 theta + cos^2 theta - 2 sin theta   cos theta)/((sin^2 theta - cos^2 theta))`

      =`(1+1)/((- cos^ 2theta )- cos^2 theta)    (∵ sin^ 2theta + cos^2 theta =1)`

     =`2/(1-2 cos^2 theta)`

     = RHS

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Chapter 8: Trigonometric Identities - Exercises 1

APPEARS IN

R.S. Aggarwal Mathematics [English] Class 10
Chapter 8 Trigonometric Identities
Exercises 1 | Q 24.2

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