Spacecurve1

A Parametric Curve in Space

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This PG code shows how to ask a parametric curve question with three answer blanks and use MultiAnswer to check the answer.

• Download file: File:Spacecurve1.txt (change the file extension from txt to pg when you save it)
• File location in NPL: FortLewis/Authoring/Templates/Parametric/Spacecurve1.pg

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PG problem file	Explanation
Problem tagging data	Problem tagging:
DOCUMENT(); loadMacros( "PGstandard.pl", "MathObjects.pl", "parserMultiAnswer.pl", "AnswerFormatHelp.pl", ); TEXT(beginproblem());	Initialization: Since we will have multiple answer blanks that depend on each other, we need to use parserMultiAnswer.pl.
Context("Numeric"); Context()->variables->are(t=>"Real"); Context()->variables->set(t=>{limits=>[0,10]}); $a = random(-5,-2,1); $x = Formula("$a * t**2"); $y = Formula("0"); $z = Formula("t"); $multians = MultiAnswer($x, $y, $z)->with( singleResult => 1, checker => sub { my ( $correct, $student, $self ) = @_; my ( $xstu, $ystu, $zstu ) = @{$student}; return 0 unless $xstu->isFormula; if (($xstu==$a*$zstu**2) && ($ystu==0)) { return 1; } else { return 0; } } );	Setup: We use singleResult => 1 since it doesn't make sense to say that x(t) is correct but z(t) is incorrect since they depend on one another. First, we check that the student hasn't fed us a bogus constant solution such as x=y=z=0 by requiring the x-coordinate to be a formula (not a constant) via return 0 unless $xstu->isFormula;. Then, we check that the student's answers satisfy the parametric equation.
Context()->texStrings; BEGIN_TEXT Find a parametrization of the curve \( x = $a z^2 \) in the \(xz\)-plane. Use \( t \) as the parameter for all of your answers. $BR $BR \( x(t) = \) \{$multians->ans_rule(20)\} \{ AnswerFormatHelp("formulas") \} $BR \( y(t) = \) \{$multians->ans_rule(20)\} \{ AnswerFormatHelp("formulas") \} $BR \( z(t) = \) \{$multians->ans_rule(20)\} \{ AnswerFormatHelp("formulas") \} END_TEXT Context()->normalStrings;	Main Text: Notice that we use $multians->ans_rule(20) (instead of just ans_rule(20)) so that the multianswer object is aware of all of the answer blanks.
$showPartialCorrectAnswers = 0; ANS($multians->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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