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Re: What's in an expression?

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  • Subject: [mg132418] Re: What's in an expression?
  • From: Murray Eisenberg <murray at>
  • Date: Tue, 11 Mar 2014 03:36:28 -0400 (EDT)
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One way, which doesn't involve looking at the form of the student's 
symbolic answer, is something employed by a at least one of the popular 
on-line homework systems: evaluate the "correct" answer at a number of 
judiciously chosen numerical values of x, evaluate the student's answer 
at the same values of x, and check that they're the same (within fuzz).

Otherwise, you may have to deal with a myriad of possible forms in which 
the student might submit an answer without actually doing what you want.
On Mar 10, 2014, at 4:38 AM, sam.takoy at 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

Murray Eisenberg                                murray at
Mathematics & Statistics Dept.      
Lederle Graduate Research Tower      phone 240 246-7240 (H)
University of Massachusetts               
710 North Pleasant Street                
Amherst, MA 01003-9305

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