** Using WeBWorK **

What determines whether or not an answer gets reduced when it's displayed? In one problem (shown below), the answer displays as a "full" equation (no simplification), where in others, the answer gets simplified down to a single number. I know that using the reduce function can at least play a part in this, but I'm not using it anywhere. In fact, using it on the answer in the below example doesn't even change the answer, despite there being a coefficient of 1 in one place.

## DESCRIPTION

##

## ENDDESCRIPTION

## DBsubject()

## DBchapter()

## DBsection()

#############################################

# Initialization

DOCUMENT();

loadMacros(

 "PGstandard.pl",

 "MathObjects.pl",

 # Needed to support graph generation.

 "PGgraphmacros.pl",

 "unionTables.pl",

 # Used to provide contextual help for how to type answers.

 "AnswerFormatHelp.pl",

 # Provides greater control over the layout of the problem.

 "PGML.pl",

 # Used for course-specific initializations.

 "PGcourse.pl",

);

TEXT(beginproblem());

# Refreshes the graph image every time the page is loaded, as opposed to

# retrieving a cached version.

$refreshCachedImages = 1;

#############################

# Setup

Context("Numeric");

# Value initialization.

$a = random(0,3,1);

$f = Compute("sqrt(x)+$a");

# Graph values

$minX = -5;

$minY = -5;

$maxX = 5;

$maxY = 5;

$originX = 0;

$originY = 0;

$gridHoriz = $maxX-$minX;

$gridVert = $maxY-$minY;

$shadedMinX = 1;

$shadedMinY = 0;

$shadedMaxX = 4;

$shadedMaxY = $f->eval(x=>$shadedMaxX);

# Converts $f to LaTeX for display later.

$ftex = $f->TeX;

# Calculates the value for the answer.

$answer = Compute("(2/3) * (4^(3/2) - 1) + 3*$a");

# Initialize graph at the required size.

$gr = init_graph($minX,$minY,$maxX,$maxY,grid=>[$gridHoriz,$gridVert],axes=>[$originX,$originY],size=>[300,300]);

$gr->lb('reset');

# Initializes the x-axis positive and negative number labels.

foreach my $i (1..$maxX-1) {

 $gr -> lb(new Label ( $i,-0.25, $i,'black','center','middle'));

}

foreach my $i (1..-$minX-1) {

 $gr -> lb(new Label (-$i,-0.25,-$i,'black','center','middle'));

}

# Initializes the y-axis positive and negative number labels.

foreach my $i (1..$maxY-1) {

 $gr -> lb(new Label (-0.25,$i,$i,'black','center','middle'));

}

foreach my $i (1..-$minY-1) {

 $gr -> lb(new Label (-0.25,-$i,-$i,'black','center','middle'));

}

# Define new graph colors

# Not all of these are used, but they are defined for easier use later.

$gr->new_color("skyblue", 86,180,233); # RGB

$gr->new_color("darkskyblue", 38,79,233);

$gr->new_color("orange", 230,159,0);

$gr->new_color("darkorange", 182, 58, 0);

#

# Choose colors

#

$light = "skyblue";

$dark = "darkskyblue";

# Graph the function and the filled region

add_functions($gr, "$f for x in <0,5> using color:$dark and weight:4");

$gr->moveTo(1,$a+1);

# Draws lines below function line to form boundary of shaded area.

$gr->lineTo($shadedMinX,$shadedMinY,$dark,4);

$gr->lineTo($shadedMaxX,$shadedMinY,$dark,4);

$gr->lineTo($shadedMaxX,$shadedMaxY,$dark,4);

# Fills in area that needs to be shaded.

$gr->fillRegion([$shadedMinX + 0.1, $shadedMinY + 0.1,$light]

);

#############################

# Main Text

# Defines the problem text.

# Places the following information in column1 (the leftmost) of the layout table.

$column1 = PGML::Format(<<END_PGML);

Use the graph to find the area of the shaded

region under [``f(x) = $ftex``].

Area = [______________][@ AnswerFormatHelp("numbers") @]*

END_PGML

# Places graph image in right-hand column.

$column2 = image( insertGraph($gr),height=>300,width=>300,tex_size=>800 ).

$BR.$BCENTER.

$BR.

"Graph of \( y = f(x) \)".

$ECENTER;

TEXT(ColumnTable($column1, $column2, indent => 0, separation => 30, valign => "TOP"));

#############################

# Answer Evaluation

# Setting this to 1 means that students will receive feedback on whether their

# answers are correct.

$showPartialCorrectAnswers = 1;

ANS($answer->cmp());

#############################

# Solution

BEGIN_PGML_SOLUTION

Solution explanation goes here.

END_PGML_SOLUTION

COMMENT('Uses PGML. Looks like pi.');

ENDDOCUMENT();

I am having an issue with problems re-randomizing on each access or reload of the browser page. This was not an issue in the past, having used these same problems from about 2005 to around 2011.
Basically, the problem accesses a macro to give students information about a particular element (atomic number, symbol, etc). They are then to answer some simple information about the element. What is happening now is that if a student answers incorrectly they get a new element and not the one thsy answered. If they simply refresh the page without any answer entry, they also get a new element.
Previously the student's numbers would persist as they do in most problems. I am wondering if the issue is with list_random or something else. Using ww and pg 2.12 on ubuntu 16.04.
Any help would be appreciated.

Here is the code I am referencing:
DOCUMENT(); # This should be the first executable line in the problem.
loadMacros(
"PG.pl",
"PGbasicmacros.pl",
"PGchoicemacros.pl",
"PGanswermacros.pl",
"PGauxiliaryFunctions.pl",
"isotopes.pl"
);
TEXT(&beginproblem);
$showPartialCorrectAnswers = 1;

@atomic_numbers = keys %isotopes;

$Z = list_random(@atomic_numbers);


$name = $isotopes{$Z}{name};
$symbol = $isotopes{$Z}{symbol};

for $who ( @{ $isotopes{$Z}{atomic_mass} } ) {
@atomic_mass = $who->{at_mass};
}

$A = list_random(@atomic_mass);

BEGIN_TEXT
How many protons are in a neutral atom of $name?
$BR

Number of protons = \{ans_rule(15)\} $BR

END_TEXT

$protons = $Z;

&ANS(num_cmp($protons,reltol=>1,format=>'%0.4g') );
ENDDOCUMENT();

The macro file has the basic structure:

%isotopes=( 1=>{name=>Hydrogen, symbol=>H, atomic_mass=> [{at_mass=>1}, {at_mass=>2}, ],}, 2=>{name=>Helium, symbol=>He, atomic_mass=> [{at_mass=>4}, {at_mass=>3}, ],}, 3=>{name=>Lithium, symbol=>Li, atomic_mass=> [{at_mass=>6}, {at_mass=>7}, ],}, 5=>{name=>Boron, symbol=>B, atomic_mass=> [{at_mass=>11}, {at_mass=>10}, ],},

Please check the file ls-R on /usr/share/<some tex path> (/usr/share/texlive/texmf-dist/ls-R in ubuntu) and see if path.sty is listed there. If not run texhash as root and refresh that list. That could possibly solve your path.sty not found issue.

Hello,

Hi Joel,

DOCUMENT();

loadMacros(
"PGstandard.pl",
"MathObjects.pl",
"PGML.pl",
"scaffold.pl",
"PGcourse.pl",
"PGgraphmacros.pl",
"PGinfo.pl",
);
#$refreshCachedImages=1;
# the above line is not needed if we are adding random numbers to the image name

TEXT(beginproblem());

Context("Numeric");
Context()->variables->are(t=>'Real');
$answer1 = Compute("sin(t)");

Scaffold::Begin(
  can_open => "when_previous_correct",
  is_open  => "first_incorrect"
);

Section::Begin("Part 1: The first part");
BEGIN_PGML
Enter [` \sin(t) `] [________]{$answer1}
END_PGML
Section::End();

$answer1_student = $inputs_ref->{ANS_NUM_TO_NAME(1)}; # alternate, perhaps more direct method

$gr = init_graph(-4,-1,4,1,
axes=>[0,0],
grid=>[8,2],
size=>[400,400]
);
$gr->imageName($gr->imageName."-".time);
#TEXT( "graph name ", $gr->imageName);
#$V_out = Formula("cos(t )");
#$G0 = FEQ(qq! $V_out for t in <-4,4> using color:blue and weight:2!);
#($f1n) = plot_functions( $gr, $G0 );
add_functions($gr, "$answer1_student for t in <-4,4> using color:blue and weight:2");

Section::Begin("Part 2: The second part");
BEGIN_PGML
The student's first answer was [$answer1_student].  

Here's a graph of the student's answer:

[@ image( insertGraph($gr), width=>200,height=>200,tex_size=>800 ) @]*
END_PGML

Section::End();

Scaffold::End();

ENDDOCUMENT();

Hello:

Is there a way to let WeBWorK accept any variable? For example, if the correct solution is {x|x>1}, and if a student typed in {Z|Z>1}, it would be considered correct?

Thank you!

Carl Yao
Math Instructor
Portland Community College

Sample code is here:

# WeBWorK problem written by Carl Yao
# Portland Community College
#
# Give a graph of an inequality, write the set notation and interval notation.
# Answer is like (3, inf).
#
# Last edited by Jordan 8/28/13; Carl Yao on 7/21/13
#
# ENDDESCRIPTION

## DBsubject('Algebra')
## DBchapter('Basic Algebra')
## DBsection('Inequalities')
## KEYWORDS('linear','inequality', 'number line','set notation','interval notation')
## DBCCSS('7.EE.4')
## TitleText1('')
## EditionText1('')
## AuthorText1('')
## Section1('')
## Problem1('')
## Author('Alex Jordan, Carl Yao, Chris Hughes')
## Institution('PCC')

##############################################

DOCUMENT();

loadMacros(
"PGgraphmacros.pl",
"PGstandard.pl",
"MathObjects.pl",
"PGML.pl",
"parserPopUp.pl",
"contextInequalitySetBuilder.pl",
"PGcourse.pl",
);

##############################################
TEXT(beginproblem());
Context("Numeric");

$a = random(-4,4,0.5);

$symbol = '>';

InequalitySetBuilder::UseVerticalSuchThat();
Context("InequalitySetBuilder-Only");
$setans = Compute("{ x | x $symbol $a}");

Context("Interval");
Context()->flags->set("formatStudentAnswer"=>'parsed');
$intans = Compute("($a,inf)");
Context("Numeric");

%answer = (leftType => 'open',
rightType => 'inf', #use 'inf' regardles of +/- inf
);


$aspectRatio = 1/8;
$horPixel = 400;
$verPixel = $horPixel*$aspectRatio;
$screenXSize = $horPixel;
$screenYSize = $screenXSize*$aspectRatio;
$reach = 5;
$verticalSpace = $reach*$aspectRatio;
$hardCopyPercent = 1000; #meaning 100%


#initializing...
@gr=();

#indices will be 0..$#gr in some order, with the index of the correct graph in the 0th position.
@indices=();


#make the graphs
for $leftType ('open','closed', 'inf')
{
for $rightType ('open','closed', 'inf')
{
my $tempgr = init_graph(-$reach,-$verticalSpace,$reach,$verticalSpace,
axes=>[$reach+1,0],
size=>[$horPixel,$verPixel]
);
@ticks = ();
for my $j ((-$reach)..($reach)) {push(@ticks,$j);};

$tempgr->h_ticks(0,"black",@ticks);
$tempgr->lb( new Label(0,-$verticalSpace/5,0,'black','center','top'));

if (($leftType eq 'inf' or $rightType eq 'inf') and !(($leftType eq 'inf' and $rightType eq 'inf')))
{
$tempgr->lb( new Label($a,-$verticalSpace/5,$a,'blue','center','top'));
if ($leftType eq 'open' or $rightType eq 'open')
{
$tempgr->stamps( open_circle($a,0,'blue') )
}
else
{
$tempgr->stamps( closed_circle($a,0,'blue') )
};
$tempgr->moveTo($a,0);
if ($leftType eq 'inf') {$tempgr->arrowTo(-0.99*$reach,0,'blue',3)}
else {$tempgr->arrowTo(0.99*$reach,0,'blue',3)};
push(@gr,$tempgr);
if ($answer{leftType} ne $leftType or $answer{rightType} ne $rightType)
{push(@indices, $#gr);}
else {unshift(@indices, $#gr);}
}

}};

$alt = "Graph of an interval on a number line. There is a hollow circle at $a and everything right of that is shaded.";

##############################################
$refreshCachedImages = 1;

Context()->texStrings;
BEGIN_TEXT
Here is a graph of an interval.$PAR

$BCENTER
\{ image( insertGraph($gr[ $indices[0] ]), width=>$screenXSize, height=>$screenYSize, tex_size=>$hardCopyPercent,
extra_html_tags=>'title="$alt" alt= "$alt" align="top"' ) \}
$ECENTER
$PAR
END_TEXT
Context()->normalStrings;

BEGIN_PGML
Please type:

* *inf* for [`\infty`],
* *[$GTS]=* for [`\geq`],
* and *[$LTS]=* for [`\leq`]

Write this inequality in set-builder notation: [_____________________]


Write this inequality in interval notation: [_____________________]



END_PGML



##############################################

ANS( $setans->cmp() );

ANS( $intans->cmp() );

BEGIN_PGML_SOLUTION

Since the given graph shades all the values greater than [`[$a]`] (but not equal to [`[$a]`]) the graph represents the inequality [`x [$symbol] [$a]`].

The corresponding set notation is [`[$setans]`].

The corresponding interval notation is [`[$intans]`].

END_PGML_SOLUTION

ENDDOCUMENT();

I did a git pull on my MathJax directory and then simply refreshed the Chrome page. Fixed immediately. Just sayin...it was that easy.

I would like the students to be able to always use the same notation for infinity in their answers, that is, I=infinity, -I=-Infinity. I know how to do this when the answer is just I or -I, but I am not able to get the answer evaluator to accept 

Thank you Alex and David!