About 25% of my students are not having the graph images displayed in their homework assignment. Combinations of Mac Pro laptops and Safari browsers are a common denominator, but some PC are also having problems.
Most of the class are getting the intended images though.
I have included a sample problem below.
Is there something I can do for these students beside direct them to campus computer labs?
A preferred browser? a change in the pg code that would make the problems more accessible?
Thanks for any guidance...
Tim
## DBsubject(Algebra)
## DBchapter(Functions)
## DBsection(Piecewise functions)
## Date(01/01/10)
## Institution(Fort Lewis College)
## Author(Paul Pearson)
## MLT(piecewise_graph_looks_like_this)
## Level(3)
## MO(1)
## TitleText1('Functions Modeling Change')
## TitleText2('Functions Modeling Change')
## TitleText3('Functions Modeling Change')
## AuthorText1('Connally')
## AuthorText2('Connally')
## AuthorText3('Connally')
## EditionText1('3')
## EditionText2('4')
## EditionText3('5')
## Section1('2.3')
## Section2('2.3')
## Section3('2.3')
## Problem1('3')
## Problem2('3')
## Problem3('3')
## KEYWORDS('functions','piecwise')
DOCUMENT();
loadMacros(
"PGstandard.pl",
"PGunion.pl",
"PGgraphmacros.pl",
"PGcourse.pl",
"PGchoicemacros.pl",
"parserPopUp.pl",
);
TEXT(beginproblem());
$refreshCachedImages=1;
##############################################
# Setup
$a = random(1,2,1);
$vshift = random(0,2,1);
while ($vshift==$a) { $vshift = random(0,2,1); }
$s = random(-1,1,2);
$amv = $a - $vshift;
$vma = $vshift - $a;
if ($s == 1) {
$f1 = Formula("-x+$vma")->reduce;
$f2 = $vshift;
$f3 = Formula("x+$vma")->reduce;
} else {
$f1 = Formula("x-$vma")->reduce;
$f2 = -$vshift;
$f3 = Formula("$amv - x");
}
#
# make graphs
#
foreach my $i (0..3) {
$G[$i] = init_graph(-4,-4,4,4,grid=>[8,8],axes=>[0,0],size=>[200,200]);
}
plot_functions($G[0],"$s*(abs(x)-$a+$vshift) for x in <-4,-$a> using color:blue and weight=2"); # correct answer
plot_functions($G[0],"$s*($vshift) for x in <-$a,$a> using color:blue and weight=2"); # correct answer
plot_functions($G[0],"$s(abs(x)-$a+$vshift) for x in <$a,4> using color:blue and weight=2"); # correct answer
$G[0] -> stamps( closed_circle(-$a,$s*$vshift,'blue') );
$G[0] -> stamps( closed_circle( $a,$s*$vshift,'blue') );
$G[0] -> lb(new Label ( 3.5,0,'x','black','left','bottom'));
$G[0] -> lb(new Label ( -0.5,3.5,'y','black','middle','center'));
plot_functions($G[1],"$s*(abs(x)-$a+$vshift) for x in <-4,-$a> using color:blue and weight=2"); # correct answer
plot_functions($G[1],"$s*($vshift) for x in <-$a,$a> using color:blue and weight=2"); # correct answer
plot_functions($G[1],"$s(abs(x)-$a+$vshift) for x in <$a,4> using color:blue and weight=2"); # correct answer
$G[1] -> stamps( open_circle(-$a,$s*$vshift,'blue') );
$G[1] -> stamps( open_circle( $a,$s*$vshift,'blue') );
$G[1] -> lb(new Label ( 3.5,0,'x','black','left','bottom'));
$G[1] -> lb(new Label ( -0.5,3.5,'y','black','middle','center'));
$bogus = random(-1,1,2);
plot_functions($G[2],"$s*(abs(x)-$a+$vshift) for x in <-4,-$a> using color:blue and weight=2"); # correct answer
plot_functions($G[2],"$s*($vshift)+$bogus for x in <-$a,$a> using color:blue and weight=2"); # correct answer
plot_functions($G[2],"$s(abs(x)-$a+$vshift) for x in <$a,4> using color:blue and weight=2"); # correct answer
$G[2] -> stamps( closed_circle(-$a,$s*$vshift,'blue') );
$G[2] -> stamps( closed_circle( $a,$s*$vshift,'blue') );
$G[2] -> stamps( open_circle(-$a,$s*$vshift+$bogus,'blue') );
$G[2] -> stamps( open_circle( $a,$s*$vshift+$bogus,'blue') );
$G[2] -> lb(new Label ( 3.5,0,'x','black','left','bottom'));
$G[2] -> lb(new Label ( -0.5,3.5,'y','black','middle','center'));
plot_functions($G[3],"$s*(abs(x)-$a+$vshift) for x in <-4,-$a> using color:blue and weight=2"); # correct answer
plot_functions($G[3],"$s*($vshift)+$bogus for x in <-$a,$a> using color:blue and weight=2"); # correct answer
plot_functions($G[3],"$s(abs(x)-$a+$vshift) for x in <$a,4> using color:blue and weight=2"); # correct answer
$G[3] -> stamps( open_circle(-$a,$s*$vshift,'blue') );
$G[3] -> stamps( open_circle( $a,$s*$vshift,'blue') );
$G[3] -> stamps( closed_circle(-$a,$s*$vshift+$bogus,'blue') );
$G[3] -> stamps( closed_circle( $a,$s*$vshift+$bogus,'blue') );
$G[3] -> lb(new Label ( 3.5,0,'x','black','left','bottom'));
$G[3] -> lb(new Label ( -0.5,3.5,'y','black','middle','center'));
foreach my $i (0..3) {
$graph[$i] = image(insertGraph($G[$i]),width=>"200",height=>"200",tex_size=>"210");
}
@perm = shuffle(4);
@fig = @graph[@perm];
@inv = invert(@perm);
@letter = ("A", "B", "C", "D");
$popup = PopUp(["?","A","B","C","D"], $letter[$inv[0]]);
##############################################
# Main text
BEGIN_TEXT
On a piece of paper, sketch a graph of the piecewise-defined function below.
\[
f(x) =
\left\lbrace
\begin{array}{lcl}
$f1, && x \leq -$a, \\
$f2, && -$a < x < $a, \\
$f3, && x \geq $a.
\end{array}
\right.
\]
$PAR
Which graph A-D below most closely matches
the graph you drew?
\{ $popup->menu() \}
$PAR
$BCENTER
\{
BeginTable().
AlignedRow([$fig[0],$fig[1],$fig[2],$fig[3]]).
TableSpace(5,0).
AlignedRow(["A","B","C","D"]).
EndTable();
\}
$BR
(Click on a graph to enlarge it.)
$ECENTER
END_TEXT
##################################################
# Answers
$showPartialCorrectAnswers = 0;
install_problem_grader(~~&std_problem_grader);
ANS($popup->cmp() );
SOLUTION(EV3(<<'END_SOLUTION'));
$PAR
$BBOLD SOLUTION $EBOLD
$PAR
The correct graph is \{ $popup->correct_ans \}.
END_SOLUTION
ENDDOCUMENT();