Chapter 10 - Analytic Geometry - 10.4 Summary of the Conic Sections - 10.4 Exercises - Page 996: 33

No graph

$$\eqalign{ & \frac{{{x^2}}}{4} + \frac{{{y^2}}}{4} = - 1 \cr & {\text{Multiply by 4}} \cr & {x^2} + {y^2} = - 4 \cr & {\text{The equation is in the form }}{x^2} + {y^2} = {r^2} \cr & {r^2}{\text{ is negative, then the equation does not represent a graph}} \cr} $$