The formula to determine the focus of a parabola is just the pythagorean theorem. C is the distance to the focus. c2 =a2 + b2
![](images/formula-focus-of-hyperbola.gif)
How to determine the focus from the equation
The formula to determine the focus of a parabola is just the pythagorean theorem. C is the distance to the focus. c2 =a2 + b2