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Find \(\frac{dy}{dx}\), if x=log(tant) and y=log(sint).(a) 2 cos^2t(b) cos^22t(c) cos^2t(d) -cos^2tThis question was posed to me during an interview.My enquiry is from Derivatives of Functions in Parametric Forms topic in division Continuity and Differentiability of Mathematics – Class 12 |
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Answer» RIGHT ANSWER is (C) cos^2t The EXPLANATION is: Given that, x=log(tant) and y=log(sint) \(\frac{dx}{dt}\)=\(\frac{1}{tant}.sec^2t=cott sec^2t\) \(\frac{dy}{dt}=\frac{1}{sin \,t}.cos \,t=cot \,t\) ∴\(\frac{dy}{dx}\)=\(\frac{dy}{dt}.\frac{dt}{dx}=\frac{cot\,t}{cot\,t sec^2t}=\frac{1}{sec^2t}=cos^2t\). |
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