GraphTool
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This article is under construction. Use the information herein with caution until this message is removed. |
Graph Tool
This example shows how to get student input in the form of a graph (a circle) by using interactive graphing tools.
| PG problem file | Explanation |
|---|---|
DOCUMENT(); loadMacros( "PGstandard.pl", "MathObjects.pl", "PGML.pl", "parserGraphTool.pl" ); TEXT(beginproblem()); |
Initialization: It is important to include the parseGraphTool.pl macro. |
$h = non_zero_random(-5, 5);
$k = non_zero_random(-5, 5);
$r = random(1, 4);
Context()->variables->add("y" => "Real");
$circle_eq_lhs = Formula("(x-$h)^2 + (y-$k)^2")->reduce;
# This grader allows the student to graph the correct circle multiple times. The idea is that
# the graph is graded based on appearance. No matter how many times the student graphs the
# correct circle, the resulting graph appears the same.
$gt = GraphTool("{circle, solid, ($h, $k), ($h + $r, $k)}")->with(
bBox => [-11, 11, 11, -11],
cmpOptions => {
list_checker => sub
{
my ($correct, $student, $ans, $value) = @_;
return 0 if $ans->{isPreview};
my $score = 0;
my @errors;
my $count = 1;
# Get the center and point that define the correct circle and compute the square of
# the radius.
my ($cx, $cy) = $correct->[0]->extract(3)->value;
my ($px, $py) = $correct->[0]->extract(4)->value;
my $r_squared = ($cx - $px) ** 2 + ($cy - $py) ** 2;
my $pointOnCircle = sub
{
my $point = shift;
my ($x, $y) = $point->value;
return ($x - $cx) ** 2 + ($y - $cy) ** 2 == $r_squared;
};
for (@$student)
{
my $nth = Value::List->NameForNumber($count++);
$score += 1, next
if ($_->extract(1) eq $correct->[0]->extract(1) &&
$_->extract(2) eq $correct->[0]->extract(2) &&
$_->extract(3) == $correct->[0]->extract(3) &&
$pointOnCircle->($_->extract(4)));
push(@errors, "The $nth object graphed is not a " . $correct->[0]->extract(1)),
next if ($_->extract(1) ne $correct->[0]->extract(1));
push(@errors, "The $nth object graphed should be a " . $correct->[0]->extract(2) . " circle."),
next if ($_->extract(2) ne $correct->[0]->extract(2));
push(@errors, "The $nth object graphed is incorrect.");
}
return ($score, @errors);
}
}
);
|
Setup: Notes: on using this and related Contexts. |
BEGIN_PGML [@ image(insertGraph($graph_image), width => 300, tex_size => 1000) @]* END_PGML |
Main Text: This is how to insert the tikz image. Note the width and tex_size parameters can change the size of the image on the web and as hardcopy. |
ENDDOCUMENT(); |
This doesn't have a question, so we aren't checking an answer. |
