## Calculus 8th Edition

$\dfrac{y^{2}}{4}-\dfrac{x^{2}}{21}=1$; equation of a hyperbola.
From the given points, we have $a=2$ and $c=5$ Thus, $c^2=a^2+b^2$ or, $5^2=2^2+b^2$ $b^2=25-4=21$ Hence, $\dfrac{y^{2}}{4}-\dfrac{x^{2}}{21}=1$; equation of a hyperbola.