Question

How do I find the directrix of a hyperbola?

Answer 1

The directrix is the vertical line `x=(a^2)/c`.

Explanation:

For a hyperbola `(x-h)^2/a^2-(y-k)^2/b^2=1`,

where `a^2+b^2=c^2`,

the directrix is the line `x=a^2/c`.