Practice!

Sample Problem

What is the equation of an ellipse with center at the origin, a vertex at (0,6) and a focus at (,0)?

(A)

(B)

(C)

(D)

Solution

Because the vertex is at (0,6), we know that a2 has to be the denominator of y and b2 has to be the denominator or x. In order to find b:

c2=a2-b2

(3√3)2=62-b2

27 = 36 - b2

b2=9

b = 3

Thus, we have