Difference between revisions of "IntervalEvaluators"
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Revision as of 15:19, 18 January 2008
Interval Answer Checkers: PG Code Snippet
This code snippet shows the essential PG code to check intervals as student answers. Note that these are insertions, not a complete PG file. This code will have to be incorporated into the problem file on which you are working.
| PG problem file | Explanation |
|---|---|
Context("Interval");
# to allow open or closed intervals, uncomment
# the following line.
# Context()->flags->set(ignoreEndpointTypes=>1);
$int = Compute("(1,3)");
|
No changes are necessary in the tagging and description and initialization sections of the question file. In the problem set-up section of the file, we set the Context to be the Interval Context. Once we're in the Interval context, we can define intervals as we'd expect: as shown here, or with limits at infinity: $int2 = Compute("(-inf,1]");
Would give the interval from negative infinity to 1, including the point at one. Note the Context flag to make endpoint checking "fuzzy." |
BEGIN_TEXT
On what interval is the parabola
\( y = (1-x)(x-3) \)
above the \(x\)-axis?
$BR
For \(x\) in \{ ans_rule(15) \}
END_TEXT
|
In the text section of the file, we ask the question as usual. |
ANS( $int->cmp() ); |
And in the answer and solution section of the file, we can check the answer using our interval MathObject. |
