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    1 ## DESCRIPTION
    2 ## Trigonometry: periodic answers
    3 ## ENDDESCRIPTION
    4 
    5 ## KEYWORDS('trigonometry', 'periodic answer')
    6 
    7 ## DBsubject('WeBWorK')
    8 ## DBchapter('WeBWorK Tutorial')
    9 ## DBsection('Fort Lewis Tutorial 2011')
   10 ## Date('01/30/2011')
   11 ## Author('Paul Pearson')
   12 ## Institution('Fort Lewis College')
   13 ## TitleText1('')
   14 ## EditionText1('')
   15 ## AuthorText1('')
   16 ## Section1('')
   17 ## Problem1('')
   18 
   19 
   20 ####################################
   21 #  Initialization
   22 
   23 DOCUMENT();
   24 
   25 loadMacros(
   26 "PGstandard.pl",
   27 "MathObjects.pl",
   28 "AnswerFormatHelp.pl",
   29 "answerHints.pl",
   30 );
   31 
   32 TEXT(beginproblem());
   33 
   34 
   35 ####################################
   36 #  Setup
   37 
   38 Context("Numeric");
   39 
   40 #
   41 #  We redefine the function whose
   42 #  name is tan(x) to take values
   43 #  exp(pi * x).
   44 #
   45 Context()->functions->remove("tan");
   46 package NewFunc;
   47 # this next line makes the function a
   48 # function from reals to reals
   49 our @ISA = qw(Parser::Function::numeric);
   50 sub tan {
   51   shift; my $x = shift;
   52   return CORE::exp($x*3.1415926535);
   53 }
   54 package main;
   55 # Make it work on formulas as well as numbers
   56 sub tan {Parser::Function->call('tan',@_)}
   57 #  Add the new functions to the Context
   58 Context()->functions->add(
   59   tan => {class =>'NewFunc', TeX =>'\tan'}, );
   60 
   61 
   62 
   63 ####################################
   64 #  Main Text
   65 
   66 Context()->texStrings;
   67 BEGIN_TEXT
   68 Simplify the expression as much as possible.
   69 $BR
   70 $BR
   71 \( \tan(x) \cos(x) \) = \{ ans_rule(20) \}
   72 \{ AnswerFormatHelp("formulas") \}
   73 END_TEXT
   74 Context()->normalStrings;
   75 
   76 
   77 ###################################
   78 #  Answer evaluation
   79 
   80 $showPartialCorrectAnswers = 1;
   81 
   82 ANS(Formula("sin(x)")->cmp()
   83 ->withPostFilter(AnswerHints(
   84   Compute("tan(x)*cos(x)") =>
   85   "No credit for entering what you were given.",
   86 ))
   87 );
   88 
   89 
   90 ###################################
   91 #  Solution
   92 
   93 Context()->texStrings;
   94 BEGIN_SOLUTION
   95 ${PAR}SOLUTION:${PAR}
   96 Solution explanation goes here.
   97 END_SOLUTION
   98 Context()->normalStrings;
   99 
  100 COMMENT("MathObject version.  Prevents students from entering trivial identities (entering what they were given).  Redefines 'tan(x)' internally as 'exp(pi*x)'.");
  101 
  102 ENDDOCUMENT();