[LON-CAPA-users] Using symbols for "infinity" in responses

[Raeburn, Stuart]

Hello Rex,

The LON-CAPA javascript previewer available for forumularresponse items will display Unicode characters for inf and minf in the preview, but the text entered in the "Submit Answer" textbox by the student will be what is submitted by the web form.

(See: the enode.js file in loncom/html/adm/LC_math_editor/src/enode.js in the LON-CAPA source repository -- source.loncapaorg/cgi-bin/cvsweb.cgi/ for the mapping to Unicode.

Maxima itself supports: inf, minf, and -inf

formularesponse with a preprocessor routine to convert INF or Inf to all inf in a student's submission before sending to Maxima for evaluation is what I would do in the current LON-CAPA.

>
> I was just wondering about whether there is (or should be) a "standardized" way to do it. 
>

Internally in LON-CAPA, a routine: maxima_cas_formula_fix() in lonmaxima.pm is used to (a) take care of implicit multiplication, and (b) convert pi to %pi, if pi is present, unless pi happens to be within a variable name (e.g., pie).

If conversion of INF and Inf were to be made "standard" (i.e., without use of an author-defined preprocessor routine) then the likely approach would be to include an appropriate regular expression in maxima_cas_formula_fix().

Stuart Raeburn
LON-CAPA Academic Consortium
________________________________________
From: LON-CAPA-users <lon-capa-users-bounces at mail.lon-capa.org> on behalf of Rex Abert <abertr at tcc.fl.edu>
Sent: Wednesday, May 27, 2020 8:24 AM
To: lon-capa-users at mail.lon-capa.org
Subject: Re: [LON-CAPA-users] Using symbols for "infinity" in responses

I was just wondering about whether there is (or should be) a "standardized" way to do it.  I have decided that what I will do is use a formula response with preprocessing to make student responses case-insensitive.

Rex

On 5/26/20 6:13 PM, Justin Gray wrote:
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Hi Rex,

I see that Purdue has a guide on Entering Math Expressions in LON-CAPA at
https://www.math.purdue.edu/academic/files/courses/2016summer/MA16010/EnteringMathExpressionsinLON-CAPA.pdf<https://urldefense.com/v3/__https://www.math.purdue.edu/academic/files/courses/2016summer/MA16010/EnteringMathExpressionsinLON-CAPA.pdf__;!!HXCxUKc!lYy8XPbj8zY_tsKaNb2xijqlp21RW7Kz2eD4WPcy7I2taPcH9ReQgDnUlHB9kA$>

While it is possible to author questions in LON-CAPA that accept this syntax, I do not believe that this is strict Maxima syntax:

Infinity is written as inf
Negative infinity is written as minf (though I think -inf will still work)
The constant pi is written %pi
The exponential function is written as %e^(x) or exp(x)

ln(x) is written as log(x) - this is confusing to students but you could write a mathresponse problem to redefine ln(x) to be log(x) in the answer algorithm if you want.
ln(x) is otherwise interpreted as l*n*x which makes accepting equivalent answers difficult.

Best,
Justin

--

Justin Gray
Senior Lecturer | Department of Mathematics
Simon Fraser University | SCK 10531
8888 University Dr., Burnaby, B.C. V5A 1S6
Canada
T: 778.782.4237

Simon Fraser University is located on the Unceded Coast Salish Territories of the xʷməθkʷəy̓əm (Musqueam), Səl̓ílwətaʔ/Selilwitulh (Tsleil-Waututh), Kwikwitlem, and Skwxwú7mesh Úxwumixw (Squamish) Peoples


On Tue, May 26, 2020 at 5:34 AM Rex Abert <abertr at tcc.fl.edu<mailto:abertr at tcc.fl.edu>> wrote:
I am developing some <formularesponse> questions for Calculus I limits
at infinity.  Sometimes the answer is +infinity or -infinity, sometimes
a constant (horizontal asymptote).  If I set the correct response as
"inf" (lowercase), the previewer correctly interprets the symbol as
expected.  A guide published by Purdue suggests that all caps should be
used, "INF."  I had the answer in a question set as "-inf" and a student
entered "-INF" and it was marked incorrect, as Maxima should, because
uppercase and lowercase symbols are different to Maxima.

I guess I am just looking for clarification on a standard way to do this
in LC, given the behavior of the javascript previewer.

--
Rex Abert
Professor of Mathematics
Tallahassee Community College



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--
Rex Abert
Professor of Mathematics
Tallahassee Community College