Hi, On Oct 21, 2013, at 10:23 AM, Angus Findlay <afind...@mta.ca> wrote:
> When I give students formula response questions some of them don’t submit > valid mathematic expressions. The most common problems are: > > 1) Not having balanced brackets. (i.e. number of left brackets do not match > number of right brackets) > 2) Including invalid characters, such as quotation signs. > 3) Not including brackets, when necessary. (eg. 2^-1/2 instead of 2^(-1/2)) > > I want to tell them that the expression is invalid, tell them why, and allow > them to enter it again, without penalty. (Right now my LON-CAPA server times > out on them, and asks them to try again later.) > > Is there a piece of standard code I can use for this, or if not, what it the > easiest to implement a solution to this? You can use <customresponse> (available now) and intercept the answer before passing it on to the symbolic algebra system, or you can use the pre-processor before the formulas are passed on to the regular <mathresponse> or <formularesponse> - but I am not sure if the pre-process argument is in 2.10.1, and whether or not it will be in 2.11. I have no prefabricated piece of code on hand. I continue to be puzzled by the students' inability to produce valid expressions - it seems like there are very few rules, and they presumably used those $@$!$# graphing calculators for years … - Gerd. _______________________________________________ LON-CAPA-users mailing list LON-CAPA-users@mail.lon-capa.org http://mail.lon-capa.org/mailman/listinfo/lon-capa-users
