[ww-bugs] Bug 4420: New: The answer demanded, and the solution displayed, are not the most general possible

[bugzilla-daemon at webwork.maa.org]

http://bugs.webwork.maa.org/show_bug.cgi?id=4420

           Summary: The answer demanded, and the solution displayed, are
                    not the most general possible
           Product: Problem Libraries
           Version: unspecified
          Platform: All
               URL: Library/Michigan/gateways/integral/topic_logarithms/pr
                    ob11.pg_with_problemSeed=412
        OS/Version: All
            Status: NEW
          Severity: minor
          Priority: P3
         Component: Library (OPL)
        AssignedTo: gjennings at csudh.edu
        ReportedBy: jadler at american.edu
        Web browser Firefox
           version:
    Browser version 72.0.2
            number:


Generally speaking, a problem in the library that asks for an antiderivative of
1/t demands an answer like ln(abs(t)), and answers of the form ln(t) are marked
wrong.

However, this problem does not demand the absolute value, and the displayed
solution leaves it out.

Of course, a student who enters the correct answer will still get credit.  But
as things stand, a student whose answer is not general enough will proabably
still get credit.  And either way, the displayed solution could lead a student
astray.

Part of the fix should be simple enough.  Change

$ans = "(1/10)*(ln(t) - 8.1)^(10) + C";

to 

$ans = "(1/10)*(ln(abs(t)) - 8.1)^(10) + C";

The displayed solution is generated by a system that I don't understand.  For
someone who understands it, the fix there should also be simple.

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