Answer
$y=\frac{\sqrt{x^2-4}}{2}$
Work Step by Step
$$\frac{x^2}{4}-y^2=1$$
Solve for $y$:
$$y^2=\frac{x^2}{4}-1$$
$$y^2=\frac{x^2-4}{4}$$
$$y=\pm\sqrt{\frac{x^2-4}{4}}=\pm\frac{\sqrt{x^2-4}}{2}$$
Take the positive value:
$$y=\frac{\sqrt{x^2-4}}{2}$$
