WeBWorK Problems

Negative numbers inside a radical in Complex context

Negative numbers inside a radical in Complex context

by Alex Jordan -
Number of replies: 1
Does anyone know if there is a way to modify the Complex context so that a student could not get away with sqrt(-2) when I want them to enter sqrt(2)i?

The default counts either of these as correct solutions to say, x^2=-2.


In reply to Alex Jordan

Re: Negative numbers inside a radical in Complex context

by Davide Cervone -

There is a flag that can be set to prevent that:

    Context("Complex");
    Context()->functions->set(
      sqrt => {negativeIsComplex => 0},
    );

There is a similar flag for log. You may also want to do

    $context->operators->set(
      '^'  => {negativeIsComplex => 0},
      '**' => {negativeIsComplex => 0},
    );

so that you can't use (-2)^.5 either.