QuestionScore Part III Find the $\frac{d y}{d x}$. ( 4 scores per question. The total is 12 scores.)
12. $y=x \sin x$.
13. $y=\frac{x^{2}-1}{x^{2}+1}$.

Studdy Solution
The derivatives for the given functions are:
For $y = x \sin x$, $\frac{dy}{dx} = \sin x + x \cos x$.
For $y = \frac{x^2 - 1}{x^2 + 1}$, $\frac{dy}{dx} = \frac{4x}{(x^2 + 1)^2}$.