## DESCRIPTION
## Algebra: laws of logarithms
## ENDDESCRIPTION

## KEYWORDS('algebra', 'laws of logarithms')

## 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",
);

TEXT(beginproblem());


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

Context("Numeric");
Context()->variables->are(x=>"Real",y=>"Real",z=>"Real");
Context()->variables->set(x=>{limits=>[2,3]});
Context()->variables->set(y=>{limits=>[2,3]});
Context()->variables->set(z=>{limits=>[2,3]});

$a = random(20,40,1);
$b = random(20,40,1);
do { $c = random(20,40,1); } until ( $c != $b );

#  TeX
$expr = "\displaystyle \ln \left( \frac{ x^{$a} y^{$b} }{ z^{$c} } \right)";

$answer = Compute("$a * ln(x) + $b * ln(y) - $c * ln(z)");

Context()->operators->undefine("/","^","**");
Context()->functions->undefine("sqrt");


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

Context()->texStrings;
BEGIN_TEXT
Using laws of logarithms, write the expression 
below using sums and/or differences 
of logarithmic expressions which do not contain 
the logarithms of products, quotients, or powers.
$BR
$BR
\( \displaystyle $expr = \) 
\{ ans_rule(40) \}
\{ AnswerFormatHelp("formulas") \}
END_TEXT
Context()->normalStrings;


###################################
# Answers

$showPartialCorrectAnswers = 1;

ANS( $answer->cmp() );


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

Context()->texStrings;
BEGIN_SOLUTION
${PAR}SOLUTION:${PAR}
Solution explanation goes here.
END_SOLUTION
Context()->normalStrings;

COMMENT("MathObject version.");

ENDDOCUMENT();