Forum archive 2000-2006

David Gilliam - log or ln

David Gilliam - log or ln

by Arnold Pizer -
Number of replies: 0
inactiveTopiclog or ln topic started 9/20/2004; 3:18:15 PM
last post 9/20/2004; 3:35:41 PM
userDavid Gilliam - log or ln  blueArrow
9/20/2004; 3:18:15 PM (reads: 1349, responses: 1)
If this topic has been discussed earlier I apologize. I could not find anything about it and I have suffered long enough. This Fall we have migrated to WW 2 from WW 1.9.

Last year I recall students could use log and ln interchangably in submitting answers. I half remember that I used both in writing answers as well.

This fall I began writing problems for differential equations and right away I noticed that students seemed to be forced to use log (not ln).

For example, if I had an answer

$ans1 = "tan(atan(sqrt(3))+log(abs(sec(x))))";

The students had to put log and ln was given no credit.

I am not very knowledgable about perl or even pg for that matter but I have been getting by. My guess is that it has something to do with the answer evaluator I am using but I have tried various cominations involving function_cmp and fun_cmp which seem to involve very different syntax.

At this point I am using, e.g.,

&ANS(fun_cmp($ans1,vars => 'x', limits => [.1,.5]));

Is there a good write-up discussing when one can and can't interchangably use log and ln?

Thanks in advance

David Gilliam

<| Post or View Comments |>

userArnold K. Pizer - Re: log or ln  blueArrow
9/20/2004; 3:35:41 PM (reads: 1653, responses: 0)
Hi David,

This is a bug but the fix is easy. See the message Buggy log( ) function$2783

Note further that if you are writing problems that use the log function, you should not use log (which can be either ln( ) or logten( )depending on how the course is set up), but rather ln if you want the natual log or logten if you want log to the base ten.


<| Post or View Comments |>