There are two cases.
Case 1. If the hyperbola has equation
,
then for p < a, any ellipse whose equation is
will share the vertices (h+a,k) and (h-a,k) and the center (h,k).
Case 2. If the hyperbola has equation
,
then for p < a, any ellipse whose equation is
will share the vertices (h,k+a) and (h,k-a) and the center (h,k).
Example and graph for case 1.
<-- hyperbola
<-- ellipse
Example and graph for case 2.
<-- hyperbola
<-- ellipse
Edwin