** Using WeBWorK **

Does this example work for you?

You can nest the if statements, so that you can ask ask as many parts as you like. --Mike

Conditional questions example If , find .

DOCUMENT();
loadMacros(
        "PGbasicmacros.pl",
        "PGchoicemacros.pl",
        "PGanswermacros.pl"
);
TEXT(beginproblem(), $BR,$BBOLD, "Conditional questions example", $EBOLD, $BR,$BR);
$showPartialCorrectAnswers = 1;

$a1 = random(3,25,1);
$b1 = random(2,27,1);
$x1 = random(-11,11,1);
$a2 = $a1+5;

BEGIN_TEXT
If \( f(x) = $a1 x + $b1  \), find \( f'( $x1 ) \).
$BR $BR \{NAMED_ANS_RULE('first_answer',10) \}
$BR
END_TEXT



$ans_eval1 = num_cmp($a1);       
NAMED_ANS(first_answer => $ans_eval1);                                  

# Using named answers allows for more control.  Any unique label can be
# used for an answer.    
# (see http://webwork.math.rochester.edu/docs/docs/pglanguage/pgreference/managinganswers.html
# for more details on answer evaluator formats and on naming answers
# so that you can  refer to them later.  Look also at the pod documentation in
# PG.pl and PGbasicmacros.pl  which you can also reach at
# http://webwork.math.rochester.edu/docs/techdescription/pglanguage/index.html)

# Check to see that the first answer was answered correctly.  If it was then we
# will ask further questions.
$first_Answer = $inputs_ref->{first_answer}  # We need to know what the answer
                                              # was named.
$rh_ans_hash = $ans_eval1->evaluate($first_Answer);

# warn pretty_print($rh_ans_hash);  # this is useful technique for finding errors.
                                    # When uncommented it prints out the contents of 
                                    # the ans_hash for debugging

# The output of each answer evaluator consists of a single %ans_hash with (at
# least) these entries:
#       $ans_hash{score}        -- a number between 0 and 1
#       $ans_hash{correct_ans}  -- The correct answer, as supplied by the instructor
#       $ans_hash{student_ans}  -- This is the student's answer
#       $ans_hash{ans_message}  -- Any error message, or hint provided by
#                                                          the answer evaluator.
#       $ans_hash{type}   -- A string indicating the type of answer evaluator.
#                                         -- Some examples:
#                                               'number_with_units'
#                                               'function'
#                                               'frac_number'
#                                               'arith_number'
# For more details see
# http://webwork.math.rochester.edu/docs/docs/pglanguage/pgreference/answerhashdataype.html

# If they get the first answer right, then we'll ask a second part to the
# question ...
if (1 == $rh_ans_hash->{score} ) {

        # WATCH OUT!!:  BEGIN_TEXT and END_TEXT have to be on lines by
        # themselves and left justified!!!   This means you can't indent
        # this section as you might want to. The placement of BEGIN_TEXT
        # and END_TEXT is one of the very few formatting requirements in
        # the PG language.

BEGIN_TEXT
                $PAR Right! Now
                try the second part of the problem: $PAR $HR
                If \( f(x) = $a2 x + \{$b1+5\}  \), find \( f'( x) \).
                $BR $BR \{ NAMED_ANS_RULE('SecondAnSwEr',10) \}
                $BR
END_TEXT

$ans_eval2 = num_cmp($a2);

        NAMED_ANS(SecondAnSwEr => $ans_eval2); 

}  
ENDDOCUMENT();

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