## Precalculus (6th Edition) Blitzer

$parabola$; $ellipse$, $circle$; $hyperbola$.
We can use the value of the determinant $B^2-4AC$ to identify the types of conic section. If $B^2-4AC=0$, we have a $parabola$ If $B^2-4AC\lt0$, we have an $ellipse$ or a $circle$ If $B^2-4AC\gt0$, we have a $hyperbola$.