## WeBWorK Problems

### 'y' not defined in this context, but 'x' works

by Xiong Chiamiov -
Number of replies: 1
It's been a while since I've done any work with problem authoring, so I was a bit stumped when I was asked about this error message: ERROR caught by Translator while processing problem file:tmpEdit/setwml_testing/blankProblem.pg.admin.tmp **************** Variable 'y' is not defined in this context; see position 74 of formula at line 99 of [PG]/macros/Parser.pl Died within main::Formula called at line 99 of [PG]/macros/Parser.pl from within main::Compute called at line 48 of [TMPL]/tmpEdit/setwml_testing/blankProblem.pg.admin.tmp **************** ------Input Read 1 ## DESCRIPTION 2 ## 3 ## ENDDESCRIPTION 4 5 ## DBsubject('Algebra') 6 ## DBchapter('Basic Algebra') 7 ## DBsection('Algebraic Expressions') 8 ## Date('') 9 ## Author('') 10 ## Institution('') 11 ## TitleText1('') 12 ## EditionText1('') 13 ## AuthorText1('') 14 ## Section1('') 15 ## Problem1('') 16 17 DOCUMENT(); 18 19 loadMacros( 20 "PGstandard.pl", 21 "MathObjects.pl", 22 ); 23 24 Context("Numeric"); 25 26 $a = list_random(3, 4, 5); 27$b = list_random(1, 2, 3, 4, 5); 28 $c = list_random(2, 3); 29$d = list_random(2, 3, 4); 30 $e = list_random(3, 6); 31$f = list_random(1, 2, 3); 32 $g = list_random(2, 4); 33$h = list_random(3, 4, 5); 34 35 36 TEXT(beginproblem()); 37 Context()->texStrings; 38 BEGIN_TEXT 39 Simplify: $BR 40 41 $$(g x^a f y^b)^2$$ 42 $$(h x^e d y^c)^3$$ 43 44 \{ans_rule(6)\} 45 46 END_TEXT 47 Context()->normalStrings; 48 49 ANS(Compute( 50 "($g ^ 2) * ($h ^ 3) * x ^ (2 *$a + 3 * $e) 51 ($f ^ 2) * ($d ^ 3) * y ^ (2 *$b + 3 * \$c)" 52 )->cmp()); 53 Context()->texStrings; 54 SOLUTION(EV3(<<'END_SOLUTION')); 55 56 END_SOLUTION 57 Context()->normalStrings; 58 59 ENDDOCUMENT(); When just using x, everything is fine, which seems strange to me, but perhaps x is associated with some magic?
In reply to Xiong Chiamiov

### Re: 'y' not defined in this context, but 'x' works

by Davide Cervone -
The problem is that 'y' isn't defined in this context. :-)

The Numeric context has only one variable predefined: x. If you want additional variables, you need to add them into the context. For example

    Context("Numeric")->variables->add(y=>'Real');

when you declare the context would make y defined as well.

Davide