Point form: $a^{2x}$/x1 - $b^{2y}$/y1 = $a^2$ - $b^2$ = $c^2$. Parametric: ax/cos(theta) - by/sin(theta) = $a^2$ - $b^2$. Slope form: y = mx - m$\frac{a^2-b^2}{sqrt}$(a^{2+b}^{2m}^2). From an external point, at most 4 normals can be drawn (unlike 3 for parabola).