see here
Thanks for pointing all of that out but your information:
Does not illustrate how to go about determining the location of covertices.Hyperbola
The equation of an East-West opening hyperbola can be expressed as
When in this form, the following hold:
Center:
Vertices:
Asymptotes:
Foci:
........where
The equation of an North-South opening hyperbola can be expressed as
When in this form, the following hold:
Center:
Vertices:
Asymptotes:
Foci:
........where