[Axiom-developer] [#176 Factored Polynomials aren't differentiated correctly] Fix

[kratt6]

Changes 
http://page.axiom-developer.org/zope/mathaction/176FactoredPolynomialsArentDifferentiatedCorrectly/diff
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??changed:
-It intends to use the formula
-
It intends to use the formula 

$$\frac{d}{dx} f(x)) = \sum_{i=1}^n \frac{f(x)}{f_i(x)}\frac{d}{dx}f_i(x)$$

where

$$f(x)=\prod_{i=1}^n f_i(x).$$

Therefore, the fix is to leave away the 'fr'::

    differentiate(u:%, deriv: R -> R) ==
      ans := deriv(unit u) * ((u exquo unit(u)::%)::%)
      ans + (_+/[fact.xpnt * deriv(fact.fctr) *
       ((u exquo nilFactor(fact.fctr, 1))::%) for fact in factorList u])

Martin

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forwarded from http://page.axiom-developer.org/zope/mathaction/address@hidden