ExplicitSequence1
From WeBWorK
Sequences with Explicit Formulas
This PG code shows how to evaluate answers that are (possibly alternating) sequences with explicit formulas.
 File location in OPL: FortLewis/Authoring/Templates/Sequences/ExplicitSequence1.pg
 PGML location in OPL: FortLewis/Authoring/Templates/Sequences/ExplicitSequence1_PGML.pg
PG problem file  Explanation 

Problem tagging: 

DOCUMENT(); loadMacros( "PGstandard.pl", "MathObjects.pl", "AnswerFormatHelp.pl", ); TEXT(beginproblem()); 
Initialization: 
Context("Numeric"); Context()>variables>are(n=>"Real"); $answer = Compute("(1)^n / n!"); $answer>{test_points} = [[1],[2],[3],[4],[5],[6]]; @seq = ( "a_0 = 1", "a_1 = 1", "a_2 = \frac{1}{2}", "a_3 = \frac{1}{6}", "a_4 = \frac{1}{24}", "a_5 = \frac{1}{120}", "\ldots" ); $sequence = join(", ", @seq); 
Setup:
We set the test points to be positive integers to avoid errors when evaluating the answer. Even if you expect students to enter answers such as
We create an array of strings 
Context()>texStrings; BEGIN_TEXT Find a formula for \( n^{th} \) term of the sequence \( $sequence \). $BR $BR \( a_n = \) \{ ans_rule(20) \} \{ AnswerFormatHelp("formulas") \} END_TEXT Context()>normalStrings; 
Main Text: 
$showPartialCorrectAnswers = 1; ANS( $answer>cmp() ); 
Answer Evaluation: 
Context()>texStrings; BEGIN_SOLUTION Solution explanation goes here. END_SOLUTION Context()>normalStrings; COMMENT('MathObject version.'); ENDDOCUMENT(); 
Solution: 