Constucting a C-infinity Function

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Discussion Overview

The discussion revolves around the construction of a C-infinity function in Matlab, specifically an odd function whose time derivative remains positive. Participants explore the implications of the function's behavior as the difference between two functions, x(t) and y(t), approaches infinity.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks assistance in constructing a C-infinity odd function defined as f = x(t) - y(t), which approaches a finite limit as |x(t) - y(t)| tends to infinity.
  • Another participant questions the feasibility of the function approaching a finite value if |x(t) - y(t)| indeed goes to infinity, suggesting a possible misunderstanding regarding the limits involved.
  • A later reply proposes the idea of using a saturation function to ensure that f(t) remains finite even as x(t) - y(t) reaches high values, seeking advice on how to smoothen the function and incorporate this saturation.
  • Another participant expresses confusion about the definition of a C-infinity function in the context of Matlab, questioning how it can be continuous given Matlab's discrete nature.

Areas of Agreement / Disagreement

Participants exhibit differing interpretations of the problem, particularly regarding the behavior of the function as its arguments approach infinity. There is no consensus on the definitions or methods proposed.

Contextual Notes

There are unresolved assumptions about the definitions of C-infinity functions and the implications of continuity in a discrete computational environment like Matlab.

art777
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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
 
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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?
 
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?
 
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?
 

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