View of /trunk/NationalProblemLibrary/ASU-topics/set119LinearSystems/p33.pg

    1 ## DESCRIPTION
    2 ## Systems of Linear Equations
    3 ## ENDDESCRIPTION
    4 
    5 ## KEYWORDS('Algebra' 'Linear Equations' 'Matrix' 'Matrices' 'True' 'False')
    6 ## Tagged by tda2d
    7 
    8 ## DBsubject('Algebra')
    9 ## DBchapter('Systems of Equations and Inequalities')
   10 ## DBsection('The Algebra of Matrices')
   11 ## Date('')
   12 ## Author('')
   13 ## Institution('ASU')
   14 ## TitleText1('')
   15 ## EditionText1('')
   16 ## AuthorText1('')
   17 ## Section1('')
   18 ## Problem1('')
   19 
   20 
   21 DOCUMENT();
   22 loadMacros("PGbasicmacros.pl",
   23            "PGchoicemacros.pl",
   24            "PGanswermacros.pl",
   25 
   26 );
   27 TEXT(beginproblem(), $BR,$BBOLD, "True False Problem", $EBOLD, $BR,$BR);
   28 # Since this is a true questions, we do not usually wish to tell students which
   29 # parts of the matching question have been answered correctly and which are
   30 # incorrect.  That is too easy.  To accomplish this we set the following flag to
   31 # zero.
   32 $showPartialCorrectAnswers = 0;
   33 
   34 # True false questions are a special case of a "select list"
   35 # Make a new select list
   36 $tf = new_select_list();
   37 # $tf now "contains" the select list object.
   38 # Insert some  questions and whether or not they are true.
   39 
   40 $tf -> qa ( # each entry has to end with a comma
   41 "If a matrix is in reduced-row echelon form, then the first nonzero entry in each row is a 1 and has 0's below it.",
   42 "T",
   43 "If an augmented matrix in reduced row-echelon form has 2 rows and 3 columns (to the left of the vertical bar), then the system has infinitely many solutions.",
   44 "F",
   45 "If the bottom row of a matrix in reduced row-echelon form contains all 0's, then the system has infinitely many solutions.",
   46 "F",
   47 "If the solution to a system of linear equations is given by (4 - 2z, -3 + z, z), then (4, -3, 0) is a solution to the system.",
   48 "T",
   49 "If the bottom row of a matrix in reduced row-echelon form contains all 0's to the left of the vertical bar and a nonzero entry to the right, then the system has no solution.",
   50 "T",
   51 "If the first and second row entries of an augmented matrix are 1,1,0, and 0,1,0, respectively, then the matrix is not in reduced row-echelon form.",
   52 "T",
   53 "If the entries of the bottom row of an augmented matrix in reduced row-echelon form are 0, 1, 3, 1, then the system has no solution.",
   54 "F",
   55 "If the number of rows of an augmented matrix in reduced row-echelon form is greater than the number of columns (to the left of the vertical bar), then the system has infinitely many solutions.",
   56 "F",
   57 );   # every statement has to end with a semi-colon.
   58 
   59 # Choose two of the question and answer pairs at random.
   60 $tf ->choose(3);
   61 
   62 # Now print the text using $ml->print_q for the questions
   63 # and $ml->print_a to print the answers.
   64 
   65 BEGIN_TEXT
   66 $PAR
   67 
   68 Enter T or F depending on whether the statement is true or false.
   69 (You must enter T or F -- True and False will not work.)$BR
   70 
   71 \{ $tf-> print_q \}
   72 
   73 $PAR
   74 
   75 END_TEXT
   76 
   77 # Enter the correct answers to be checked against the answers to the students.
   78 
   79 ANS(str_cmp( $tf->ra_correct_ans )   ) ;
   80 
   81 ENDDOCUMENT();        # This should be the last executable line in the problem.