Question:
Mark $(\sqrt{ })$ against the correct answer in the following:
If $\mathrm{x}=\mathrm{a} \sec \theta, \mathrm{y}=\mathrm{b} \tan \theta$ then $\frac{\mathrm{dy}}{\mathrm{dx}}=$ ?
A. $\frac{b}{a} \sec \theta$
B. $\frac{b}{a} \operatorname{cosec} \theta$
C. $\frac{b}{a} \cot \theta$
D. none of these
Solution: