How do I find the foci of an ellipse if its equation is #x^2/16+y^2/9=1#?

Question

10502 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2014-10-04T21:28:01

#x^2/16+y^2/9=1#

#a^2=16#
#b^2=9#

The center is #(0,0)#.

The x-axis is the major axis. We know this because the #x^2# term has the larger denominator.

We find the foci using the following equation and solving for #c#.

#c^2=a^2-b^2#
#c^2=16-9#
#c^2=7#
#c=sqrt(7)#

The coordinates for the foci are #(+-c,0) -> (+-sqrt(7),0)#