I've noticed strange errors when the ranges of x and y below are changed to

[-1,1]. In that case I get this...

Error parsing answer: 'plicitEquation' is not defined in this context; see position 3 of formula

I thought the ranges of x and y were not so important but apparently there

are certain caveats to be aware of?

cs

DOCUMENT();

loadMacros(

"MathObjects.pl",

"PGstandard.pl",

"PGML.pl",

"PGcourse.pl",

"parserNumberWithUnits.pl",

"contextArbitraryString.pl",

"parserMultiAnswer.pl",

"parserPopUp.pl",

"contextInequalities.pl",

"parserImplicitEquation.pl",

"PGgraphmacros.pl",

);

TEXT(beginproblem());

$showPartialCorrectAnswers = 1;

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

Context("ImplicitEquation");

Context()->variables->set(

x=>{limits=>[-8,8]},

y=>{limits=>[-8,8]}

);

BEGIN_PGML

What is the equation for a circle with its center at (4, 2)

throught the point (3, 2)?

[________________________]{ImplicitEquation("(x-4)^2 + (y-2)^2=1",

tolerance=>0.0001)}

END_PGML

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

ENDDOCUMENT();