Hi,
what is the proper way of dealing with negative infinity in STACK? Maxima is providing the symbol minf
for limits and if I use ta: limit(-x^3,x,inf)
to calculate a correct answer the student will be told to type this answer as minf
. The expression -inf
(despite of looking exactly the same in the validation) won't be accepted (with answer test AlgEquiv).
On the other hand when dealing with intervals -inf
is occuring as well. E.g. natural_domain(sqrt(-x))
evaluates to realset(x,oc(-inf,0))
.
Is there a robust way to just use one or the other? I think it can be really confusing for students, especially if two different syntaxes would occure in the same question.
Stephan.