Q192 / 270 · NDA 2010 (Phase 2) · Mathematics
What is the derivative of $\sin ^2 x$ with respect to $\cos ^2 x$ ?
- A$\tan ^2 x$
- B$\cot ^2 x$
- Correct answerC-1
- D1
Solution
$\begin{aligned} & \text { Let } u=\sin ^2 x \\ & \text {and } v=\cos ^2 x \\ & \begin{aligned} \therefore \frac{d u}{d x} & =2 \sin x \cdot \cos x \\ \frac{d u}{d x} & =-2 \cos x \cdot \sin x \\ \therefore \quad \frac{d u}{d v} & =\frac{d u}{d x} \times \frac{d x}{d v} \\ & =\frac{2 \sin x \cdot \cos x}{-2 \sin x \cdot \cos x}=-1\end{aligned}\end{aligned}$
Hence, the correct answer is option: 'C'.