Difference between revisions of "Logarithms1"

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(Created page with '<h2>Answer Must Be Simplified Using Logarithms</h2> 300px|thumb|right|Click to enlarge <p style="background-color:#f9f9f9;border:black solid 1px;padding…')
 
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<p style="font-size: 120%;font-weight:bold">This problem has been replaced with [https://openwebwork.github.io/pg-docs/sample-problems/Algebra/Logarithms.html a newer version of this problem]</p>
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<h2>Answer Must Be Simplified Using Logarithms</h2>
  
<h2>Answer Must Be Simplified Using Logarithms</h2>
   
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This PG code shows how to disable and undefine some functions and operators, which will require students to simplify their answer using laws of logarithms.
  
This PG code shows how to disable and undefine some functions and operators, which will require students to simplify their answer using laws of logarithms.
 
</p>
  
</p>
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* Download file: [[File:Logarithms1.txt]] (change the file extension from txt to pg when you save it)
  
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* File location in OPL: [https://github.com/openwebwork/webwork-open-problem-library/blob/master/OpenProblemLibrary/FortLewis/Authoring/Templates/Algebra/Logarithms1.pg FortLewis/Authoring/Templates/Algebra/Logarithms1.pg]
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* File location in NPL: <code>FortLewis/Authoring/Templates/Algebra/Logarithms1.pg</code>
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* PGML location in OPL: [https://github.com/openwebwork/webwork-open-problem-library/blob/master/OpenProblemLibrary/FortLewis/Authoring/Templates/Algebra/Logarithms1_PGML.pg FortLewis/Authoring/Templates/Algebra/Logarithms1_PGML.pg]
   
 
<br clear="all" />
  
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"MathObjects.pl",
  
"MathObjects.pl",
 
"AnswerFormatHelp.pl",
  
"AnswerFormatHelp.pl",
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"contextLimitedPowers.pl",
  
 
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<p>
  
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<b>Setup:</b>
 
<b>Setup:</b>
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We add the variables to the context and reset their limits since logarithms are not defined on the default domain <code>[-1,1]</code>. <i>After</i> defining <code>$answer</code>, then we undefine certain operators and functions so that students will have to simplify their answer. Since the answer requires multiplication no matter how it is written, we cannot prevent students from entering an answer such as <code>ln(x*x*x...)</code> instead of <code>$a * ln(x)</code>, but by choosing the values for <code>$a, $b, $c</code> to be large, we can strongly discourage them from entering <code>ln(x*x*x...)</code>.
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We add the variables to the context and reset their limits since logarithms are not defined on the default domain <code>[-1,1]</code>. <i>After</i> defining <code>$answer</code>, then we undefine certain operators and functions so that students will have to simplify their answer. Since the answer requires multiplication no matter how it is written, we cannot prevent students from entering an answer such as <code>ln(x*x*x...)</code> instead of <code>$a * ln(x)</code>, but by choosing large values for <code>$a, $b, $c</code>, we can strongly discourage them from entering <code>ln(x*x*x...)</code>.
 
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[[Category:Top]]
  
[[Category:Top]]
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[[Category:Authors]]
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[[Category:Sample Problems]]
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[[Category:Subject Area Templates]]

Latest revision as of 04:49, 18 July 2023

This article has been retained as a historical document. It is not up-to-date and the formatting may be lacking. Use the information herein with caution.

This problem has been replaced with a newer version of this problem


Answer Must Be Simplified Using Logarithms

Click to enlarge

This PG code shows how to disable and undefine some functions and operators, which will require students to simplify their answer using laws of logarithms.


Templates by Subject Area

PG problem file Explanation

Problem tagging data

Problem tagging: 

DOCUMENT();

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

TEXT(beginproblem());

Initialization: 

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");

Setup: We add the variables to the context and reset their limits since logarithms are not defined on the default domain [-1,1]. After defining $answer, then we undefine certain operators and functions so that students will have to simplify their answer. Since the answer requires multiplication no matter how it is written, we cannot prevent students from entering an answer such as ln(x*x*x...) instead of $a * ln(x), but by choosing large values for $a, $b, $c, we can strongly discourage them from entering ln(x*x*x...). 

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;

Main Text: 

$showPartialCorrectAnswers = 1;

ANS( $answer->cmp() );

Answer Evaluation: 

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

COMMENT('MathObject version.');

ENDDOCUMENT();

Solution:

Templates by Subject Area

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