Constucting a C-infinity Function

1. Sep 25, 2006

art777

Hi!!I am trying to construct in Matlab a C-infinity Odd Finction whose time derivative is always positive. The function is; f=x(t)-y(t). The function goes to a finite limit as |x(t)-y(t)| tends to infinity. Can anyone help me?

Thanks

2. Sep 25, 2006

CRGreathouse

I don't understand the question. If |x(t)-y(t)| goes to infinity, then f(t) = x(t)-y(t) can't go to a finite value. Do you mean as t goes to infinity, perhaps?

3. Oct 23, 2006

art777

C-infinity

Thanks for the reply. Well if x(t)-y(t) goes to high values, well we need to saturate it with some kind of saturation function. That way we can make
f(t) finite. So how do we smoothen the function and incorporate saturation?

4. Oct 23, 2006

StatusX

I don't know what you mean by a C-infinity function in Matlab. Wouldn't it only be defined on a discrete set of points? In what sense is it continuous?