Differentiate `sqrt((1-x)/(1+x))` with respect to x.

Explanation

To differentiate \( \sqrt{\frac{1-x}{1+x}} \) with respect to \( x \), follow these steps:

1. **Rewrite the function**:
Let \( y = \sqrt{\frac{1-x}{1+x}} \).

2. **Apply the chain rule**:
Rewrite \( y \) as \( y = \left( \frac{1-x}{1+x} \right)^{1/2} \).

...