
Re: What's in an expression?
Posted:
Mar 11, 2014 3:16 AM


Assuming that answers are entered as strings; to exclude derivatives but allow other alternative forms:
verifySolution[proposed_, actual_, cond_: {}] := StringFreeQ[proposed, {"Derivative", "'", "D["}] && Simplify[ToExpression[proposed] == actual, cond]
answers = {"Sin'[x]", "Derivative[1][Sin][x]", "D[Sin[x],x]", "Cos[x]", "Sin[x]/Tan[x]"};
ToExpression /@ answers // Union
{Cos[x]}
verifySolution[#, Cos[x]] & /@ answers
{False, False, False, True, True}
If the answer must be literally the same as the intended answer:
verifySolution2[proposed_, actual_] := SameQ @@ (StringTrim /@ {proposed, actual})
verifySolution2[#, "Cos[x]"] & /@ answers
{False, False, False, True, False}
Bob Hanlon
On Mon, Mar 10, 2014 at 4:38 AM, <sam.takoy@yahoo.com> wrote:
> Hi all, > > I'm building a little Mathematica system that checks answers entered by > students. Suppose the question is "what is Sin'[x]?" ad the student > responds: Sin'[x] which is "correct", but not the intended answer (Cos[x]). > I'm wondering if there is a general way to approach this sort of problem. > In particular, is there a way to find out whether a given expression > includes certain elements (like Derivative)? > > Thank you in advance, > > Sam > >

