Question: Mark $(\sqrt{)}$ against the correct answer in the following:
If $\mathrm{y}=\sqrt{\frac{1+x}{1-x}}$ then $\frac{d y}{d x}=?$
A. $\frac{2}{(1-x)^{2}}$
B. $\frac{x}{(1-x)^{3 / 2}}$
C. $\frac{1}{(1-x)^{3 / 2} \cdot(1+x)^{1 / 2}}$
D. none of these
Solution:
