alt Hacker NewsTake a parabola and rotate it 90 degrees. The forumula for that is not a function of the x axis: it has two values for all but one point on the curve.
Take a parabola and rotate it 90 degrees. The forumula for that is not a function of the x axis: it has two values for all but one point on the curve.
It's still a function of many other things: y, t, angle, ...