[Axiom-developer] [#179 differentiating sums with respect to a bound is wrong] (new) differentiating sums with respect to a bound is wrong

[Bill Page]

Changes 
http://page.axiom-developer.org/zope/mathaction/179DifferentiatingSumsWithRespectToABoundIsWrong/diff
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--removed:
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--removed:
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??changed:
-                  Status:                    None => transferred            
-Example of code trigerring the bug: f:=operator 'f
Status:   None => transferred            

Example of code trigerring the bug:
\begin{axiom}
f:=operator 'f

??changed:
- => f:=operator 'f
-D(sum(f(i),i=a..x),x)
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-
-
-    _______________________________________________________
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-Reply to this item at:
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-  <http://savannah.nongnu.org/bugs/?func=detailitem&item_id=9216>
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-
\end{axiom}

is nonsense. The problem is in COMBF/dvdsum:

\begin{axiom}
dvdsum(l, x) ==
  x = retract(y := third l)@SE => 0
  k := retract(d := second l)@K
  differentiate(h := third rest rest l,x) * eval(f := first l, k, h)
  - differentiate(g := third rest l, x) * eval(f, k, g)
  + opdsum [differentiate(f, x), d, y, g, h]
\end{axiom}

Although this:

$$d/dx \sum_i^x f(i) = f(x)$$

is a nice try, it is wrong. It seems that the order of magnitude is
roughly correct, but that's about it.

Unfortunately, I do not know how to return the thing unevaluated,
so I cannot fix the bug yet



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