DOCUMENT();

loadMacros(
    "PGstandard.pl",
    "PGML.pl",
    "PGcourse.pl",
);

TEXT(beginproblem());

Context("Vector");
Context()->variables->are(x=>"Real",y=>"Real",z=>"Real");
Context()->flags->set(ijk=>1 );
Context()->constants->set(
  i => {TeX => "\,\mathit{\vec i}"},
  j => {TeX => "\,\mathit{\vec j}"},
  k => {TeX => "\,\mathit{\vec k}"},
);

$answer=Vector("<0,0,x>");

BEGIN_PGML

The answer is <0,0,x>.

Submit <0,0,0,x> first. Then try to submit correct answer.

>>Answer is [_____________________________________]{$answer} <<

END_PGML

ENDDOCUMENT();