The "manual" is clearly wrong. In fact, the whole example stinks. Setting
the modulus during rational operations is generally quite unrelated to the
uses of ratdiff, which would ordinarily be used to speed up analytic
operations, not algebraic.
I think the example should be flushed entirely.
Richard Fateman (who wrote RATDIFF in 1970 or so)
> -----Original Message-----
> From: maxima-bounces at math.utexas.edu
> [mailto:maxima-bounces at math.utexas.edu] On Behalf Of Doug Stewart
> Sent: Thursday, October 11, 2007 7:19 PM
> To: maxima at math.utexas.edu
> Subject: small problem with the manual.
>
> While trying to learn Maxima, I was going through the manual
> and came to
> the ratdiff function.
>
> It doesn't seem to work the same as what the manual shows.
>
> I am using Maxima at
>
> http://www.my-tool.com/mathematics/
>
> and am using the manual from
>
> http://www.ma.utexas.edu/maxima/maxima_11.html#IDX322
>
> the manual shows:
>
> (C1) (4*X**3+10*X-11)/(X**5+5);
> 3
> 4 X + 10 X - 11
> (D1) ----------------
> 5
> X
> (C2) MODULUS:3$
> (C3) MOD(D1);
> 2
> X + X - 1
> (D3) --------------------
> 4 3 2
> X + X + X + X + 1
> (C4) RATDIFF(D1,X);
> 5 4 3
> X - X - X + X - 1
> (D4) ------------------------------
> 8 7 5 4 3
> X - X + X - X + X - X + 1
>
>
>
> One problem is -- the denominator of the (c1) line has a
> +5 that
> doesn't show up in (D1)
>
>
> but more importantly mod doesn't work that way.
> and I can't get ratdiff to do anything like what is shown.
>
> Just thought I would point these things out as I find them.
> Doug
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