Question: Mark $(\sqrt{ })$ against the correct answer in the following:
If $\sqrt{x}+\sqrt{y}=\sqrt{a}$ then $\frac{d y}{d x}=$ ?
A. $\frac{-\sqrt{x}}{\sqrt{y}}$
B. $-\frac{1}{2} \cdot \frac{\sqrt{y}}{\sqrt{x}}$
C. $\frac{-\sqrt{y}}{\sqrt{x}}$
D. None of these
Solution:
