## PREP 2015 Question Authoring - Archived

### Free Trial webwork version 2.8 is generating "Context" errors.

by tim Payer -
Number of replies: 1
Hello all!

I just imported a number of problems into our campus' free trial webwork course version 2.8 that are getting a unknown "Context" error. These problems were working fine in webwork 2.10 that were created in the PREP 2015 course.
I would like to find a solution. Are there certain contexts that are not valid in version 2.8 webwork?

I would like to find a solution as I suspect that the MAA may not be upgrading to version 2.10 by our campus's first day of class on Monday August 24th.

I have posted the error statement below and an associated problem.
The error is happinging even with pg problems. The context("Fraction"); is also generating this error. Help please??

Many thanks....

       Problem1
ERROR caught by Translator while processing problem file:Payer/M105_HW_1/M105_H1_rat_fract_19.pg
****************
ERRORS from evaluating PG file: begin|||Unknown context 'Context' at line 130 of [PG]/macros/Parser.pl
Died within main::Context called at line 1352 of [PG]/macros/PGML.pl
from within main::_PGML_init called at line 183 of [PG]/lib/PGloadfiles.pm
from within main::loadMacros called at line 14 of (eval 16441)
|||end
1		# DESCRIPTION   Problem 17
2		# Algebra_Review
3		# WeBWorK problem written by TimPayer <tsp1@humboldt.edu>
4		# ENDDESCRIPTION
5
6		## DBsubject(Algebra)
7		## DBchapter(Fractions)
8		## DBsection(Solving Formulas)
9		## Institution(Humboldt State University)
10		## Author(Tim Payer)
11		## KEYWORDS(reduce, fraction, formulas)
12
13		DOCUMENT();
15		"PGstandard.pl",
16		"PGML.pl",
17		"MathObjects.pl",
18		"PGbasicmacros.pl",
19		"problemRandomize.pl",
20		"parserFormulaUpToConstant.pl"
21		);
22
23		Context("Numeric");
24
25		$a = Real(random(3,9,1)); 26$plus =Real(random(1,7,1));
27		$c = Compute("$a+$plus"); 28$ac = Compute("$a-$c");
29		$bm = Real(random(1,7,1)); 30$dm = Real(random(1,7,1));
31		$b = Compute("-$ac*$bm"); 32$d = Compute("-$ac*$dm");
33
35
36
37		BEGIN_PGML
38		>> Solve for [x]: <<
39
40		>> [[$a] x-[$b] = [$c] x -[$d] y] <<
41
42		>> [x] = [__________]{([$b]-[$d] y)/([$a]-[$c])} <<
43
44		END_PGML
45
46		BEGIN_PGML_SOLUTION
47		*SOLUTION*
48
49		To solve for [x] within an equation we must first isolate the terms of [x] on the left side of the equation and then push the non terms of [x] on the right side of the equation.
50		[\begin{aligned}&\\
51		[$a] x-[$b] &= [$c] x -[$d] y\\
52		- [$c] x +[$b] &= - [$c] x+ [$b] && \text{Adding and subtracting terms to push the x terms to the left side of the equation.}\\
53		[$a] x - [$c] x &= -[$d] y + [$b] && \text{Balancing the equation.}\\
54		[$ac] x &= -[$d] y + [$b] && \text{Collecting like terms.}\\ 55 \frac{[$ac] x}{ [$ac]} &= \frac{-[$d] y + [$b]}{[$ac]} && \text{Dividing by the leading coefficient.}\\
56		x &= \frac{([$ac])[$dm] y + ([$ac]) [$bm]}{[$ac]} && \text{See the common factors of the fraction.}\\ 57 x &= [$dm] y + [\$bm] && \text{Reduced.}
58		\end{aligned}]
59
60
61		END_PGML_SOLUTION
62
63		ENDDOCUMENT();


This was a problem in PGML.pl that was fixed in March 2014 (in version 2.8.1). See this comment for details.
One work-around is to make sure that MathObjects.pl is loaded beforePGML.pl in the loadMacros() call. Another would be to get the current copy of PGML.pl and put it in your course/templates/macros directory.