Equivalent Forms of Quadratics


This is a problem generator which evaluates student responses for correctness and validates each based on the specified form of the equation.

Equivalent Forms of Quadratics

Any feedback is welcome.

I was going to share this on the examples page, but after hours of work the CL is a bit too cloudy to be a clean cut example.

The validation method looks for specific numbers as opposed to values (using countNumberUsage). I am not sure if there is a way to use this with numericValue or if there is some other option for validating forms of equations. It’s flawless for equations with integer vertex and roots. However, it cannot recognize fractions, so it only works for fractions which truncate. In addition, it cannot pick-up on reduced radicands.I could probably add another layer to the validation so that it would, but this project has become too labor intensive.


I like the error messages that appear. I was surprised that it would count it as correct, even if the form was wrong, though that shouldn’t be hard to change if desired. I had never noticed the countNumberUsage command before.


I just noticed that if one of the factors is x, then you have to enter (x-0) as the factor to avoid the warning. That behavior is probably not desirable.


Thanks for the feedback! I was able to (mostly) remedy each of these issues.

I was so focused on the error message coding that I forgot to take into account that someone could still submit the answer even though the warning popped up. I was able to correct the counter.

I was able to change it so that roots of zero are automatically validated. This does present a problem still in standard form because x(x-9) and x^2-9 are both validated as correct since standard form is validating B=9 and factored form is validating the root=9.

Unfortunately, I don’t think there is a way around that though since those strings would be equivalent under countNumberUsage.