# How do you find the equation of an ellipse with foci #(+-2,0)# and major axis of length 8?

##### 1 Answer

Dec 17, 2016

#### Explanation:

The line of foci is the major axis and, here, it is the x-axis y = 0.

The center is the midpoint of the join of theci, and so, it is the origin

(0, 0 ).

The major axis 2a = 8. So, a = 4.

THe distance between the foci = 2a X (eccentricity) = 2ae = 6e = 4. So, e = 1/2.

The semi minor axis

Now, the equation is

The graph is inserted.

graph{x^2/16+y^2/12-1=0 [-10, 10, -5, 5]}