Checking an exponential equation

I would like my students to write a geometric equation for the sequence 2, 6, 18… I would like them to type in the answer as t(n)=2/3(3)^n. I have the answer written in the computation layer as
when exp10.submitted and exp10.latex = “t(n)=\frac{2}{3}(3)^n” “\n\Good work !”
when exp10.submitted “\n\Wrong answer. Please try again.”
otherwise “”
It works with arithmetic sequences, but I cannot get the equation to work with the exponent and fraction. Help!
Can someone please tell me how I need to fix my computation layer?

Checking latex is not always reliable. Using computation is more accurate. If you add a graph component (which you can hide, or use a graph from a different slide), add this into the graph CL to make a function, f, in terms of n out of the student input:
function(`f`): simpleFunction(exp10.latex,"n")

Copy the URL below into the actual graph. I tried to give explanations of each part. Let me know if anything doesn’t make sense.

Thanks for your help!