Find the coordinates of the foci and the vertices, the eccentricity,
Find the coordinates of the foci and the vertices, the eccentricity, and the length of the latus rectum of the hyperbola $5 y^{2}-9 x^{2}=36$
The given equation is $5 y^{2}-9 x^{2}=36$.
$\Rightarrow \frac{y^{2}}{\left(\frac{36}{5}\right)}-\frac{x^{2}}{4}=1$
$\Rightarrow \frac{y^{2}}{\left(\frac{6}{\sqrt{5}}\right)^{2}}-\frac{x^{2}}{2^{2}}=1$ $\ldots(1)$
On comparing equation (1) with the standard equation of hyperbola i.e., $\frac{y^{2}}{a^{2}}-\frac{x^{2}}{b^{2}}=1$, we obtain $a=\frac{6}{\sqrt{5}}$ and $b=2$
We know that $a^{2}+b^{2}=c^{2}$.
$\therefore c^{2}=\frac{36}{5}+4=\frac{56}{5}$
$\Rightarrow c=\sqrt{\frac{56}{5}}=\frac{2 \sqrt{14}}{\sqrt{5}}$
Therefore, the coordinates of the foci are $\left(0, \pm \frac{2 \sqrt{14}}{\sqrt{5}}\right)$.
The coordinates of the vertices are $\left(0, \pm \frac{6}{\sqrt{5}}\right)$.
Eccentricity, $e=\frac{c}{a}=\frac{\left(\frac{2 \sqrt{14}}{\sqrt{5}}\right)}{\left(\frac{6}{\sqrt{5}}\right)}=\frac{\sqrt{14}}{3}$
Length of latus rectum $=\frac{2 b^{2}}{a}=\frac{2 \times 4}{\left(\frac{6}{\sqrt{5}}\right)}=\frac{4 \sqrt{5}}{3}$