Find the equation of the hyperbola with eccentricity 3/2 and foci at (± 2, 0).
Given
$e=\frac{3}{2}$
We have foci $=(\pm \mathrm{a} \mathrm{e}, 0)=(\pm 2,0)$
Therefore the hyperbola lies on $x$-axis,
Equation is $\frac{\mathrm{x}^{2}}{\mathrm{a}^{2}}-\frac{\mathrm{y}^{2}}{\mathrm{~b}^{2}}=1$
Given $\mathrm{a} \mathrm{e}=2$
$a \times \frac{3}{2}=2$
$a=\frac{4}{3}$
$\because b^{2}=a^{2}\left(e^{2}-1\right)$
$b^{2}=\left(\frac{4}{3}\right)^{2}\left(\left(\frac{3}{2}\right)^{2}-1\right)$
$=\frac{16}{9}\left(\frac{9}{4}-1\right)=\frac{16}{9} \times \frac{5}{4}=\frac{20}{9}$
Equation is $\frac{x^{2}}{\left(\frac{4}{3}\right)^{2}}-\frac{y^{2}}{\frac{20}{9}}=1$
$\frac{9 x^{2}}{16}-\frac{9 y^{2}}{20}=1$
Hence, the required equation is $\frac{9 \mathrm{x}^{2}}{16}-\frac{9 \mathrm{y}^{2}}{20}=1$
Equation is $\frac{\mathrm{x}^{2}}{\left(\frac{4}{3}\right)^{2}}-\frac{\mathrm{y}^{2}}{\frac{20}{9}}=1$
$\frac{9 x^{2}}{16}-\frac{9 y^{2}}{20}=1$
Hence, the required equation is $\frac{9 \mathrm{x}^{2}}{16}-\frac{9 \mathrm{y}^{2}}{20}=1$
Equation is $\frac{\mathrm{x}^{2}}{\left(\frac{4}{3}\right)^{2}}-\frac{\mathrm{y}^{2}}{\frac{20}{9}}=1$
$\frac{9 x^{2}}{16}-\frac{9 y^{2}}{20}=1$
Hence, the required equation is $\frac{9 \mathrm{x}^{2}}{16}-\frac{9 \mathrm{y}^{2}}{20}=1$