`36 $bhalf = random(2,10,1); `

37 $b = Compute("2*$bhalf");

38

39 $index = random(1,10,1);

40 @increments = (2,3,5,6,7,8,10,11,12,13);

41 $k = @increments[$index];

42 # coefficient of y

43 $c = Compute("$k + ($b**2)/4");

44

45 $lambda = Compute("-$bhalf");

46 $discrim = Compute("-4*$k");

47 $negdiscrim = Compute("4*$k");

Yet I get the following error message when viewing as a student:

Missing operand after '*'; see position 3 of formula at line 93 of [PG]/macros/Parser.pl Died within main::Formula called at line 93 of [PG]/macros/Parser.pl from within main::Compute called at line 46 of [TMPL]/Local/Murray_PhaseAmplitudeForm.pg

Oddly, I'm getting the error only when I view this as some students and not others. The question was already deployed in a set. Most students encountered no error, apparently (and already got it correct). Yet a couple are running into the error.

Is there something in Perl syntax I'm missing here?