In each of the following, find the equation for the ellipse that satisfies the given conditions:
Length of major axis 26, foci (
5, 0)
Length of major axis = 26; foci = (
).
Since the foci are on the x-axis, the major axis is along the x-axis.
Therefore, the equation of the ellipse will be of the form
=1, where a is the semi-major axis.
Accordingly, 2a =26
a = 13 and c=5.
It is known that a2 = b2+c2.
132 = b2+42
169 = b2 + 25
b2 = 169 – 25
b =
= 12
Thus, the equation of the ellipse is
=1 or
= 1.