View of /trunk/NationalProblemLibrary/ASU-topics/set119MatrixAlgebra/p18.pg

    1 DOCUMENT();
    2 loadMacros("PGbasicmacros.pl",
    3            "PGchoicemacros.pl",
    4            "PGanswermacros.pl",
    5 
    6 );
    7 TEXT(beginproblem(), $BR,$BBOLD, "True False Problem", $EBOLD, $BR,$BR);
    8 # Since this is a true questions, we do not usually wish to tell students which
    9 # parts of the matching question have been answered correctly and which are
   10 # incorrect.  That is too easy.  To accomplish this we set the following flag to
   11 # zero.
   12 $showPartialCorrectAnswers = 0;
   13 
   14 # True false questions are a special case of a "select list"
   15 # Make a new select list
   16 $tf = new_select_list();
   17 # $tf now "contains" the select list object.
   18 # Insert some  questions and whether or not they are true.
   19 
   20 $tf -> qa ( # each entry has to end with a comma
   21 "If A and B are both square matrices such that AB equals BA equals the identity matrix, then B is the inverse matrix of A.",
   22 "T",
   23 "If A is a square matrix, then there exists a matrix B such that AB equals the identity matrix.",
   24 "F",
   25 "If \( AX = B \) represents a system of linear equations and \( A^{-1} \) exists, then the product \( A^{-1}B \) gives the solution to the system.",
   26 "T",
   27 );   # every statement has to end with a semi-colon.
   28 
   29 # Choose two of the question and answer pairs at random.
   30 $tf ->choose(2);
   31 
   32 # Now print the text using $ml->print_q for the questions
   33 # and $ml->print_a to print the answers.
   34 
   35 BEGIN_TEXT
   36 $PAR
   37 
   38 Enter T or F depending on whether the statement is true or false.
   39 (You must enter T or F -- True and False will not work.)$BR
   40 
   41 \{ $tf-> print_q \}
   42 
   43 $PAR
   44 
   45 END_TEXT
   46 
   47 # Enter the correct answers to be checked against the answers to the students.
   48 
   49 ANS( str_cmp( $tf->ra_correct_ans )   ) ;
   50 
   51 ENDDOCUMENT();        # This should be the last executable