InequalityEvaluators

Inequalities as Answers

This is the essential code for having inequalities as student answers.

Problem Techniques Index

PG problem file	Explanation
DOCUMENT(); loadMacros( "PGstandard.pl", "contextInequalities.pl", "PGcourse.pl", ); TEXT(beginproblem());	Initialization: Include the macro file contextInequalities.pl.
Context("Inequalities"); Context()->variables->add(y=>"Real"); # Context()->constants->add(EmptySet => Set()); # Context()->flags->set(noneWord=>"EmptySet"); # f(x) = x^2 - 16 on -1 <= x <= 5 $range = Compute("-16 <= y <= 9");	Setup: Using Context("Inequalities"), if the student enters either the inequality -16 <= y <= 9 or the interval [-16,9] their answer will be marked correct. To mark only the inequality correct but not the interval, use Context("Inequalities-Only"); instead. Uncommenting the lines containing EmptySet creates an empty set as a named constant and uses that name. As of January 2010, the inequality is not variable-specific, so the answer -16 <= x <= 9 would also be marked correct. We could have required students to use the variable y by removing the default variable x from the context using are instead of add when setting variables. For example, Context()->variables->are(y=>"Real");. For a list of all available options for the interval context, see the POD documentation at http://webwork.maa.org/doc/cvs/pg_CURRENT/macros/contextInequalities.pl
BEGIN_TEXT What is the range of \( y = f(x) = x^2 - 16 \) on the domain \( -1 \leq x \leq 5 \)? Enter your answer using inequalities or intervals. $BR $BR Range: \{ ans_rule(20) \} END_TEXT	Main Text: The problem text section of the file is as we'd expect.
ANS( $range->cmp() ); ENDDOCUMENT();	Answer Evaluation: As is the answer.

Problem Techniques Index