Find the equation of the ellipse whose vertices are at (±6, 0) and foci at (±4, 0).
Given: Vertices = (±6, 0) …(i)
The vertices are of the form = (±a, 0) …(ii)
Hence, the major axis is along x – axis
∴ From eq. (i) and (ii), we get
a = 6
⇒ a2 = 36
and We know that, if the major axis is along x – axis then the equation of Ellipse is of the form of
Also, given coordinate of foci = (±4, 0) …(iii)
We know that,
Coordinates of foci = (±c, 0) …(iv)
∴ From eq. (iii) and (iv), we get
c = 4
We know that,
c2 = a2 – b2
⇒ (4)2 = (6)2 – b2
⇒ 16 = 36 – b2
⇒ b2 = 36 – 16
⇒ b2 = 20
Substituting the value of a2 and b2 in the equation of an ellipse, we get