Find the equation of the ellipse whose foci are (4, 0) and (- 4, 0), eccentricity = 1/3.
Given that we need to find the equation of the ellipse whose eccentricity is
and foci (±4,0).

Let us assume the equation of the ellipse as
(a2>b2).
We know that eccentricity(e) = ![]()
⇒ ![]()
⇒ ![]()
⇒ ![]()
⇒ ![]()
We know that foci = (±ae,0)
⇒ ae = 4
⇒ ![]()
⇒ a = 12
⇒ a2 = 144
⇒ ![]()
⇒ b2 = 128
The equation of the ellipse is
⇒ ![]()
∴ The equation of the ellipse is
.