Rationalized Question (Correctness?)

Questions
1

I am wondering why the correct sink is not treating these the same…Am I missing something?

-\frac{2}{\sqrt{3}} and -\frac{2\sqrt{3}}{3}

Here is the slide: Testing (-2sqrt3)/3 vs (-2/sqrt3) • Activity Builder by Desmos

Thank you for your help!!!

2

This happens sometimes with numericValue. Try using simpleFunction instead (although it still doesn’t recognize the two being equivalent, so I put both ways):

correct: correct

correct = simpleFunction(this.latex).evaluateAt(0) = simpleFunction("-\frac{2}{\sqrt{3}}").evaluateAt(0) 
or simpleFunction(this.latex).evaluateAt(0) = simpleFunction("-\frac{2\sqrt{3}}{3}").evaluateAt(0)
3

Thank you! I’m curious, what value does simpleFunction("-\frac{2\sqrt{3}}{3}").evaluateAt(0) equal?

4

Well it’s a function with a constant -2sqrt(3)/3. There’s no x so it doesn’t matter what number it’s being evaluated at. It’s just that however desmos calculates the decimal value comes out slightly different for the two forms. Notice in the picture the difference is NOT zero, even though a and b appear to be equal.
image