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Question
Prove that:
(1+ cot2 A) (1 − cos A) (1 + cos A) = 1
Sum
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Solution
Solving L.H.S. of the equation:
⇒ (1 + cot2 A)(1 − cos A)(1 + cos A)
⇒ (1 + cot2 A)(1 − cos2 A)
By formula,
1 + cot2 A = cosec2 A and 1 − cos2 A = sin2 A.
⇒ cosec2A × sin2A
⇒ `1/(sin^2A) × sin^2A`
⇒ 1
Since, L.H.S. = R.H.S.
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Chapter 21: Trigonometrical Identities - TEST YOURSELF [Page 342]
