Which property is shared by all points (x,y)(x, y)(x,y) on an ellipse x2a2+y2b2=1\frac{x^2}{a^2} + \frac{y^2}{b^2} = 1a2x2+b2y2=1?
The sum of distances to two fixed points (foci) is constant.
The distance to the origin is constant.
The distance to a fixed point equals the distance to a fixed line.
The product of distances to the axes is constant.