Disabling Functions

Disable functions and require exact fractions as answers.

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Complete Code

Download file: DisableFunctionsTrig.pg

POD for Macro Files

PG problem file

Explanation

DOCUMENT();

loadMacros('PGstandard.pl', 'PGML.pl', 'contextFraction.pl', 'PGcourse.pl');

Preamble

The contextFraction.pl is loaded for the Fraction-NoDecimals context.

Context('Fraction-NoDecimals');

$f1 = Formula('cos(pi)');
$f2 = Formula('sin(pi / 3)');

Context()->functions->disable('All');
Context()->functions->enable('sqrt');

$answer1 = Compute('-1');
$answer2 = Compute('sqrt(3) / 2');

Setup

Select the Fraction-NoDecimals context which requires fractions as answers and does not allow decimals.

After constructing the formulas involving trig functions, disable all functions and re-enable the sqrt function. This means fractions and square roots can be entered, but an error message will be shown if any other function is entered.

BEGIN_PGML
Enter your answers as simplified fractions.

+ [`[$f1] =`] [_]{$answer1}{15}

+ [`[$f2] =`] [_]{$answer2}{15}
END_PGML

Statement

This is the problem statement in PGML. 
BEGIN_PGML_HINT
The cosine of an angle is zero when the angle is an integer multiple of [`\pi`].
END_PGML_HINT

Hint

A hint is provided.

BEGIN_PGML_SOLUTION
Provide a solution here.
END_PGML_SOLUTION

ENDDOCUMENT();

Solution

A solution should be provided here.