###########################################################
#
#  Example showing how to use the Parser to make
#  a formula that you can evaluate and print in TeX form.
#

DOCUMENT();        # This should be the first executable line in the problem.

loadMacros(
  "PGbasicmacros.pl",
  "PGanswermacros.pl",
  "Parser.pl",
);

TEXT(beginproblem());

###########################################################
#
#   The setup
#
Context('Vector');

#
#   Define a vector
#
$a = non_zero_random(-8,8,1);
$b = non_zero_random(-8,8,1);
$c = non_zero_random(-8,8,1);

$V = $a*i + $b*j + $c*k;  # equivalently: $V = Vector($a,$b,$c);

###########################################################
#
#  The problem text
#

Context()->texStrings;
BEGIN_TEXT

The length of the vector \($V\) is \{ans_rule(20)\}.

END_TEXT
Context()->normalStrings;

###########################################################
#
#  The answer
#

ANS(num_cmp(norm($V)->value));  # easier:  ANS($V->cmp)
$showPartialCorrectAnswers = 1;

###########################################################

ENDDOCUMENT();        # This should be the last executable line in the problem.