Explanation

Hyperbola foci lie outside the hyperbola.

Formula:
c² = a² + b²

If transverse axis is horizontal:
Foci: (±c, 0)

If vertical:
Foci: (0, ±c)

Key property:
The difference of distances from any point to the foci is constant.

Quiz

1. How many foci does a hyperbola have?

2. What formula finds c?

3. Are the foci inside or outside?

4. Where are the foci if the hyperbola opens up/down?

5. What stays constant for a hyperbola?

Answer Key

1. Two

2. c² = a² + b²

3. Outside

4. (0, ±c)

5. Difference of distances