Find the equation of the director circle of the hyperbola x216−y29=1\frac{x^2}{16} - \frac{y^2}{9} = 116x2−9y2=1.
x2+y2=25x^2 + y^2 = 25x2+y2=25
x2+y2=7x^2 + y^2 = 7x2+y2=7
x2+y2=0x^2 + y^2 = 0x2+y2=0
No director circle exists