[Maxima] Fourier Series for unit step

Richard Hennessy rvh2007 at comcast.net
Mon May 12 11:35:41 CDT 2008

```You are right, never mind.  The answer should be

if x<0 then 0 elseif equal(z,0) then und else 0

or

if x<0 then 0 elseif equal(z,0) then errmsg1 else 0

I didn't think that through enough.  Silly me.

Anyway this was a bad example function, if the function was continuous and differentiable at 0 then this would still be a good idea.
Rich

------------Original Message------------
From: "Stavros Macrakis" <macrakis at alum.mit.edu>
To: "Richard Hennessy" <rvh2007 at comcast.net>
Cc: "Maxima List" <maxima at math.utexas.edu>
Date: Sun, May-11-2008 9:42 PM
Subject: Re: [Maxima] Fourier Series for unit step

On Sun, May 11, 2008 at 7:49 PM, Richard Hennessy <rvh2007 at comcast.net> wrote:
> You claim I said this, "2*inf is not equal to inf", but I didn't

So you want it to be the case that a=b does not imply that
integrate(a)=integrate(b)+C?

> I did say "There is no information loss here which is the overriding concern to me.

Well, your convention doesn't help with diff( if equal(x,0) then 1
else 0 ) or diff( if x<0 then 0 elseif x>0 then 1 else k ).

And what do you propose that diff(5,x) be?  The unsimplified form 5*0?
You could of course set things up so that every differentiation
carries around its original argument, e.g. diff(5,x) => 0 <<from:
diff(5,x)>> but then what do you do with diff(5,x)-diff(3,x)?  Does
this become 0 <<from: (0 <<from: diff(5,x)>> + 0 <<from:
diff(3,x)>>)>> etc.?  Or how about 5-5?  Should that be represented as
0 <<from: 5-5>>?

-s

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