Question$2 W$ Mark for Review $4 \%$
Consider the curve in the $x y$-plane defined by $x^{2}-\frac{y^{2}}{5}=1$. It is known that $\frac{d y}{d x}=\frac{5 x}{y}$ and $\frac{d^{2} y}{d x^{2}}=-\frac{25}{y^{3}}$. Which of the following statements is true about the curve in Quadrant IV? A) The curve is concave up because $\frac{d y}{d x}>0$.
B The curve is concave down because $\frac{d y}{d x}<0$.
C The curve is concave up because $\frac{d^{2} y}{d x^{2}}>0$.
D The curve is concave down because $\frac{d^{2} y}{d x^{2}}<0$.