# SampleProblem4

## A PGML WeBWorK Sample Problem

This sample problem illustrates the basics of how to use PGML commands to layout a question. This sample just scratches the surface of what is possible using these mark up commands. Page through the sample questions to see what can be done and click on the "show problem source" button to see how to accomplish it.

As usual a standard WeBWorK PG file has five sections:

1. A tagging and description section, that describes the problem for future users and authors,
2. An initialization section, that loads required macros for the problem,
3. A problem set-up section that sets variables specific to the problem,
4. A text section, that gives the text that is shown to the student, and
5. OPTIONAL --An answer , that specifies how the answer(s) to the problem is(are) marked for correctness, and gives a solution that may be shown to the student after the problem set is complete. As you will see this section can be used but are not necessary when using PGML commands.
6. A solution section

The sample file attached to this page shows this; below the file is shown to the left, with a second column on its right that explains the different parts of the problem that are indicated above.

PG problem file Explanation
# DESCRIPTION
# A simple sample problem that asks students to
# differentiate a trigonometric function.
# WeBWorK problem written by Gavin LaRose
# <glarose(at)umich(dot)edu>
# and modified by Mike Gage   gage(at)math(dot)rochester(dot)edu
# ENDDESCRIPTION

## DBsubject('WeBWorK')
## DBchapter('Demos')
## DBsection('Problem')
## KEYWORDS('')
## TitleText1('')
## EditionText1('')
## AuthorText1('')
## Section1('')
## Problem1('')
## Author('Gavin LaRose')
## Institution('UMich')


This is the tagging and description section of the problem. Note that any line that begins with a "#" character is a comment for other authors who read the problem, and is not interpreted by !WeBWorK.

The description is provided to give a quick summary of the problem so that someone reading it later knows what it does without having to read through all of the problem code.

All of the tagging information exists to allow the problem to be easily indexed. Because this is a sample problem there isn't a textbook per se, and we've used some default tagging values. There is an on-line list of current chapter and section names and a similar list of keywords. The list of keywords should be comma separated and quoted (e.g., KEYWORDS('calculus','derivatives')).

DOCUMENT();
"PGstandard.pl",
"PGML.pl",
"MathObjects.pl",
"PGcourse.pl",
);


This is the initialization section of the problem. The first executed line of the problem must be the DOCUMENT(); command. Note that every command must end with a semicolon.

The loadMacros command loads information that works behind the scenes. We load the PGML.pl file to load the PGML formatting commands (similar to markDown) and the PGcourse.pl file to provide any local course customizations. The PGcourse.pl file is usually placed in the courses templates/macros directory 

 
# make sure we're in the context we want
Context("Numeric");
$showPartialCorrectAnswers = 1;$f = Formula("cos^2(x)+sin^2(x)");


This is the problem set-up section of the problem. Context("Numeric"); sets the "context", which determines how variables are interpreted. Contexts and context explanations are given on this help page. Setting showpartialCorrectAnswers to 1 means that feedback as to which sub-questions have been correctly answered in the problem, otherwise the feedback indicates that there is a wrong answer somewhere. (Use the latter mode for multiple choice or true false questions.)

The bulk of the set-up section defines variables that we use in the rest of the problem. All scalar variables are prefaced with a dollar sign: thus $a is a variable that has a (non-vector, non-array) value. . TEXT(beginproblem()); #TEXT(PGML::Format2(<<'END_PGML')); BEGIN_PGML The number twelve is [_______]{12} Type the formula [1+\frac{x}{2}] [__________]{"1+x/2"} Twelve is [______]{Real(12)} 2 mod 10 is [______]{Real(2)->with(period=>10)} [[$f]] is equal to [_______]{Real(1)}
Twelve is [______]{num_cmp(12)}

END_PGML



This is the text section of the problem. The TEXT(beginproblem()); line displays a header for the problem. Everything between the BEGIN_PGML and END_PGML lines (each of which must appear alone on a line) is shown to the student. BEGIN_PGML and END_PGML replace the BEGIN_TEXT/END_TEXT structure used in the other template samples. The Context()->texStrings line is not needed. (If you are not using the latest version of pg you may need to replace BEGIN_PGML with its expanded version TEXT(PGML::Format2(<<'END_PGML')); which is

Answer blanks are indicated by [______] where the number of blanks indicates the width of the answer blank. The correct answer can be given in curly braces immediately afterward {"1+x/2"}. TeX formulas can be entered as  [1+\frac{x}{2}]  or in calculator notation as [:1+x/2:}  [[$f]]  typesets the formula$f in inline math mode.

A link to an interactive online calculator and to several dozens examples of using PGML is on the PGLabs page. Here is the typeset version of this sample problem

SOLUTION(PGML::Format2(<<'END_SOLUTION'))
$PAR SOLUTION$PAR

You can use PGML in your solution if you use the structure
above.  There is currently no short cut.
END_SOLUTION
Context()->normalStrings;

ENDDOCUMENT();


This is the answer and solution section of the problem. The answers were given along side the problems using PGML so the answer section is not needed although it is allowed.

Then, we explain the solution to the student. Currently there is no short cut for using PGML in the solution section, but one can use the long version as above.

The ENDDOCUMENT(); command is the last command in the file.