InterviewSolution
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InterviewSolution
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Evaluate \(\sqrt {\frac {1 – sin \, A}{1 + sin \, A}}\).(a) cos A + tan A(b) cos A – tan A(c) tan A – cot A(d) sec A + tan AThis question was posed to me in unit test.This intriguing question comes from Trigonometric Identities in section Trigonometry of Mathematics – Class 10 |
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Answer» CORRECT option is (d) sec A + TAN A Best explanation: \(\SQRT {\frac {1 – sin \, A}{1 + sin \, A}} = \sqrt {\frac {1 – sin \, A}{1 + sin \, A}} . \sqrt {\frac {1 – sin \, A}{1 – sin \, A}}\) = \(\frac {\sqrt {(1 + sin \, A)^2}}{\sqrt {1 – sin^2} \, A} \) = \(\frac {1 + sin \, A}{\sqrt {cos^2} \, A}\)(∵ sin^2 A + cos^2 A = 1) = \(\frac {1 + sin \, A}{cos \, A}\) = sec A + tan A |
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