MathAction #207 certain limit failure

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Consider the following two expressions:

fricas

(1) -> exa:=integrate(log(1/x)/x^a,x)

$\label{eq1}\frac{{{\left(- a + 1 \right)}\ x \ {\log \left({\frac{1}{x}}\right)}}+ x}{{\left({{a}^{2}}-{2 \ a}+ 1 \right)}\ {{e}^{-{a \ {\log \left({\frac{1}{x}}\right)}}}}}$

(1)

Type: Union(Expression(Integer),...)

fricas

exb:=integrate(log(1/x)*x^b,x)

$\label{eq2}\frac{{\left({{\left(b + 1 \right)}\ x \ {\log \left({\frac{1}{x}}\right)}}+ x \right)}\ {{e}^{-{b \ {\log \left({\frac{1}{x}}\right)}}}}}{{{b}^{2}}+{2 \ b}+ 1}$

(2)

Type: Union(Expression(Integer),...)

which are equivalent by setting . However, the operation limit doesn't like both equally well:

fricas

limit(exa,x=0)

   >> Error detected within library code:
   can not determine sign

fricas

limit(exb,x=0)

   >> Error detected within library code:
   can not determine sign

Martin

Now they both fail, as they should.

... --test1, Mon, 05 Oct 2015 17:46:54 +0000 reply

Status: open => fixed somewhere

Subject: Be Bold !!

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