[ww-bugs] Bug 2474: New: Domain restriction needed for diffeq solution

[bugzilla-daemon at webwork.maa.org]

http://bugs.webwork.maa.org/show_bug.cgi?id=2474

           Summary: Domain restriction needed for diffeq solution
           Product: Problem libraries
           Version: unspecified
          Platform: PC
        OS/Version: Mac OS
            Status: NEW
          Severity: enhancement
          Priority: P5
         Component: Library
        AssignedTo: jj at asu.edu
        ReportedBy: zullil at lafayette.edu
        Web browser ---
           version:


NationalProblemLibrary / WHFreeman /
Rogawski_Calculus_Early_Transcendentals_Second_Edition /
9_Introduction_to_Differential_Equations / 9.1_Solving_Differential_Equations /
9.1.27.pg

The largest *interval* on which the solution to the initial-value problem
exists is (-pi/2, pi/2). It makes sense to include "Assume \( -\pi/2 < t <
\pi/2 \)." in the very statement of the problem.

More important, the domain of the solution must be restricted in the problem
code, so that sensible values are used when answer-checking. As is, the correct
solution e^ln(3 sec(t) ) is called incorrect when the seed value is 3072, for
example.

Need something like 

$fp = Formula("$c* sec(t)")->with(limits=>[-1,1])->reduce();

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