Step 1 :We are given the function \(y=\frac{x}{x+1}\) and asked to find the second derivative, \(\frac{d^{2} y}{d x^{2}}\).
Step 2 :First, we find the first derivative of the function. Using the quotient rule, we get \(y' = -\frac{x}{(x + 1)^2} + \frac{1}{x + 1}\).
Step 3 :Next, we find the second derivative by differentiating the first derivative. This gives us \(y'' = \frac{2x}{(x + 1)^3} - \frac{2}{(x + 1)^2}\).
Step 4 :However, none of the given options match this result. Let's simplify the expression for the second derivative.
Step 5 :After simplifying, we find that \(y'' = -\frac{2}{(x + 1)^3}\).
Step 6 :\(\boxed{-2(x+1)^{-3}}\) is the correct answer, which matches option B.