# [PD] bouncing

Mathieu Bouchard matju at artengine.ca
Sat Oct 13 17:32:34 CEST 2007

```On Sat, 13 Oct 2007, marius schebella wrote:

> I haven't heard it before, but tried to translate it from german
> (steigungswinkel)
> any line that is defined by f(x)=ax+b and where a!=0

That's called "linear" or "affine" equation.

In one terminology, "linear" is the general case, and "linear
homogeneous" when b=0.

In another terminology, "affine" is the general case, and "linear" is when b=0.

But that's probably not all that you want to support: you want also to
support f(x)=b and the non-function case of a vertical line. The thing is,
functions of 1 variable to 1 variable are all that they teach people in
high-school, but if you want to compute things in which y and x are
considered of equal importance and not hierarchised, you have to stop
considering one as the function of the other. You could, for example, use
plain equations (not functions) for things that don't move, and consider
y,x to be functions of t for things that move.