## DESCRIPTION
## Trigonometry: disable functions and require exact fractions as answers.
## ENDDESCRIPTION

## KEYWORDS('trigonometry', 'exact answer')

## DBsubject('WeBWorK')
## DBchapter('WeBWorK Tutorial')
## DBsection('Fort Lewis Tutorial 2011')
## Date('01/30/2011')
## Author('Paul Pearson')
## Institution('Fort Lewis College')
## TitleText1('')
## EditionText1('')
## AuthorText1('')
## Section1('')
## Problem1('')


###########################
#  Initialization

DOCUMENT();

loadMacros(
"PGstandard.pl",
"MathObjects.pl",
"AnswerFormatHelp.pl",
"contextFraction.pl",
);

TEXT(beginproblem());


###########################
#  Setup

Context("Fraction-NoDecimals");

$f1 = Formula("cos(pi)");
$f2 = Formula("sin(pi/3)");

Context()->functions->disable("All");
Context()->functions->enable("sqrt");

$answer1 = Compute("-1");
$answer2 = Compute("sqrt(3)/2");


###########################
#  Main text

Context()->texStrings;
BEGIN_TEXT
Enter your answers as simplified fractions.
$BR
$BR
\( $f1 = \)
\{ ans_rule(20) \}
\{ AnswerFormatHelp("fractions") \}
$BR
$BR
\( $f2 = \)
\{ ans_rule(20) \}
\{ AnswerFormatHelp("fractions") \}
END_TEXT
Context()->normalStrings;


###########################
#  Answer evaluation

$showPartialCorrectAnswers = 1;

ANS( $answer1->cmp() );

ANS( $answer2->cmp() );


###########################
#  Solution

Context()->texStrings;
BEGIN_SOLUTION
${PAR}SOLUTION:${PAR}
The cosine of an angle is zero when 
the angle is an integer multiple of \( \pi \).
END_SOLUTION
Context()->normalStrings;

COMMENT('MathObject version.');

ENDDOCUMENT();