# Write the equation of an ellipse with a major axis of length 8 and co-vertices (0, 3) and (0, -3).

*print*Print*list*Cite

### 1 Answer

The general form for an ellipse is `x^2/a^2+y^2/b^2=1` , assuming the ellipse is centered at the origin. If a>b the major axis is horizontal, if a<b the major axis is vertical.

The vertices lie along the major axis. If a>b they are (a,0),(-a,0).

The covertices lie on the minor axis; if a>b then they are (0,b),(0,-b).

We are given the covertices as (0,3) and (0,-3) so the major axis is horizontal. From this we get b=3.

The length of the major axis is 2a -- since the length is 8 we have a=4.

---------------------------------------------------------------

The equation is `x^2/16+y^2/9=1`

----------------------------------------------------------------

The graph: