PointAnswers1

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Answer is a Point or a List of Points

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This PG code shows how to evaluate answers that are points or lists of points.



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PG problem file Explanation

Problem tagging data

Problem tagging:

DOCUMENT();

loadMacros(
"PGstandard.pl",
"MathObjects.pl",
"AnswerFormatHelp.pl",
"contextLimitedPoint.pl",
);

TEXT(beginproblem());

Initialization: We only need to load contextLimitedPoint.pl if we want to prevent operations between points.

Context("LimitedPoint");

$f = Compute("x^2-1");

$xint = List( Point("(1,0)"), Point("(-1,0)") );

$yint = List( Point("(0,-1)") );

Setup: We could have used Context("Point"); instead, which would allow mathematical operations between points (such as adding points as if they were vectors). The x-intercepts are clearly a list of points. We used a list with only one element for the y-intercepts so that a student who mistakenly enters two points will be told their second point is incorrect. If we did not use a list for the y-intercepts, a student who enters two points would be given an error message instead.

Context()->texStrings;
BEGIN_TEXT
Enter the x-intercept(s) and y-intercept(s)
of \( y = $f \).  Enter a point as \( (a,b) \),
including the parentheses.  If there is more 
than one correct answer, enter a comma 
separated list of points.
$BR
$BR
x-intercept(s): \{ ans_rule(20) \}
\{ AnswerFormatHelp("points") \}
$BR
y-intercept(s): \{ ans_rule(20) \}
\{ AnswerFormatHelp("points") \}
END_TEXT
Context()->normalStrings;

Main Text: Be sure to tell students the proper syntax for how to enter their answers.

$showPartialCorrectAnswers = 1;

ANS( $xint->cmp() );

ANS( $yint->cmp() );

Answer Evaluation:

Context()->texStrings;
BEGIN_SOLUTION
${PAR}SOLUTION:${PAR}
Solution explanation goes here.
END_SOLUTION
Context()->normalStrings;

COMMENT('MathObject version.');

ENDDOCUMENT();

Solution:

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