Question

An ellipse has foci at (±4, 0) and vertices at (±5, 0). What is the eccentricity of the ellipse?

I went to a couple websites, I understand the equation is c/a for eccentricity, but different websites say different things for what "a" is. One place says a is the distance from the center to the vertex, another says a is the distance from the focus to the vertex? Which is it? help me do this problem please?

Answer 1

@phi

Answer 2

a is the distance from the center to the vertex

Answer 3

a=5

Answer 4

So my equation would be 4/5, or .8?

Answer 5

yes

Answer 6

ok thanks!

Answer 7

more questions

Answer 8

No, that pretty much covers it haha

Answer 9

cool