A hyperbola centered at the origin has a vertex at [tex]$(0,36)$[/tex] and a focus at [tex]$(0,39)$[/tex].
\begin{tabular}{|l|l|}
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Vertices: [tex]$(-a, 0), (a, 0)$[/tex] & Vertices: [tex]$(0, -a), (0, a)$[/tex] \\
Foci: [tex]$(-c, 0), (c, 0)$[/tex] & Foci: [tex]$(0, -c), (0, c)$[/tex] \\
Asymptotes: [tex]$y = \pm \frac{b}{a} x$[/tex] & Asymptotes: [tex]$y = \pm \frac{a}{b} x$[/tex] \\
Directrices: [tex]$x = \pm \frac{a^2}{c}$[/tex] & Directrices: [tex]$y = \pm \frac{a^2}{c}$[/tex] \\
Standard Equation: [tex]$\frac{x^2}{a^2} - \frac{y^2}{b^2} = 1$[/tex] & Standard Equation: [tex]$\frac{y^2}{a^2} - \frac{x^2}{b^2} = 1$[/tex] \\
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\end{tabular}
Which are the equations of the directrices?
[tex]$x = \pm \frac{12}{13}$[/tex]