Say that I want to ask the students to integrate 2*sin(x)*cos(x), and I want them to be allowed to write any of the following answers (forgetting the +C for now): (sin(x))^2 , -(cos(x))^2 , -1/2 cos(2x).

Is there a way to do that? For now, here is my simple code with answer (sin(x))^2:

DOCUMENT();

loadMacros(

"PGstandard.pl",

"PGML.pl",

"PGcourse.pl"

);

TEXT(beginproblem());

$f = Formula("2*sin(x)*cos(x)");

$F = Formula("(sin(x))**2");

$ans = $F;

BEGIN_PGML

[`` \int [$f] \, dx = ``] [_______________________]{$ans} [` +C `]

END_PGML

ENDDOCUMENT;

I tried creating another answer

$G = -Formula("(cos(x))**2");

and writing the answer with an 'or' in it as

$ans = ($F||$G);

but it did not work.

Any help would be appreciated. Thank you!