(Difference between revisions)

PG problem file Explanation
```DOCUMENT();
"PGstandard.pl",
"MathObjects.pl",
"parserImplicitPlane.pl",
);
TEXT(beginproblem());
```

Initialization: We need to include the macros file `AnswerFormatHelp.pl`.

```Context("ImplicitPlane")->variables->are(x=>"Real",y=>"Real");

```

Setup: By declaring there are only two variables, `ImplicitPlane` will address objects as lines rather than planes.

```BEGIN_TEXT
Enter an equation for a line through the points
\( (0,2) \) and \( (2,0) \).
\$BR
\$BR
\{ ans_rule(20) \}
END_TEXT
```

Main Text: We use `AnswerFormatHelp("equations")` to generate a link to an html help file with link text `help (equations)`. The html help files are specifically designed to help students figure out the correct syntax for their answer, as well as common mistakes to avoid. We recommend placing a help link immediately after each answer blank in a problem, especially if there are different types of answers. Currently, help files are available for

• angles
• decimals
• exponents
• formulas
• fractions
• inequalities
• intervals
• logarithms
• limits
• numbers
• points
• syntax
• units
• vectors

It is possible to change the link text to `help entering equations` by including a second argument to the routine:

```\{ AnswerFormatHelp("equations","help entering equations") \}
```

It is possible to provide a link to an external file. We do not recommend this as it requires external files be maintained and links not become broken. Fields marked bogus are unused, but necessary, placeholders.

```\{ AnswerFormatHelp("bogus","help (formulas)",
"http://webwork.someschool.edu/dir/subdir/") \}
```

It is possible to write your help document directly into the PG file as the fourth field to `AnswerFormatHelp`. This keeps the help documentation internal to the PG file and is therefore preferable to providing a link to an external file.

```\{ AnswerFormatHelp("bogus",
"custom help on formulas (internal source)",
"bogus",
"<h3>  Help With Something</h3>
<ul>
<li><font color='#222255'>Header 1:</font> Some text with
some math    <code>ln(x)</code><br /><br /></li>
<li><font color='#222255'>Header 2:</font> Some more text
with stuff below indented <blockquote>More text</blockquote>
<br /></br></li>
</ul>
<br /><br />") \}
```

```\$showPartialCorrectAnswers = 1;

ENDDOCUMENT();
```