DIsallowing the use of trigonometric functions inside math input

Dear all,

I would like to disallow the use of trigonometric functions in some of my activities. For example, I would ask the student to find x, but I don`t want him to answer as 3 tan(1/2 arctan(2/3)) [I’d rather want them to answer as 3/2 (sqrt(13)-3) or even 0.908]. I couldn’t find a way to do that. Could you help me please?

No way to disable it, but you can tweak your correctness check to distinguish between the different forms. For that particular answer,

correct = numericValue("\round(${i},3)")=0.908 and 
 or (countNumberUsage(i,3)=2 and countNumberUsage(i,2)=1 and 

So, first checking if rounded the value is correct to 3 decimal places, then if there’s one number (i.e. 0.908), or if 3 is present twice, and 2 and 13 are present, once each, in the answer. So, the trig answer will be marked incorrect because it doesn’t have the right number usage.

You could also identify the trig answer in a similar way to give some specific feedback if you felt inclined.

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