NAME

contextMatrixExtras.pl - Add transpose, trace, and determinant to Matrix context

DESCRIPTION

The contextMatrixExtras.pl file adds the ability to include matrix transpose, trace, and determinants in student answers. The transpose is represented by ^T, as in M^T, in student answers or parsed strings. The trace is given as tr(M), and the determinant by det(M). Thus you can do things like:

loadMacros("contextMatrixExtras.pl");

Context("Matrix");
Context()->constants->add(
    A => Matrix([[pi,1/pi**2],[sqrt[2],ln(pi)]]),  # an arbitrary matrix with no special properties
);

$F = Formula("det(A) + tr(A^T)");

Context()->texStrings;
BEGIN_TEXT
\($F\) = \{ans_rule(20)\}
END_TEXT
Context()->normalStrings;

ANS($F->cmp);

You can also use the trace, det, and transpose methods of a Matrix object to compute these in PG code.

loadMacros("contextMatrixExtras.pl");

Context("Matrix");
$M = Matrix([[1,2],[3,4]]);

$Mt = $M->transpose;
$d  = $M->det;
$tr = $M->trace;

Note that the contextMatrixExtras.pl file modifies the Matrix context, so be sure to load it before you set the Context.