I am trying to figure out how to write a WW problem that asks to combine like terms for a trig polynomial:
Any help would be great!
Isn't it that you just want to replace different powers of x with different trig functions?
23.b is the same as 23.a but x^2 replaced with cosine square and x replaced with cosine.
I would use the problems in Rochester/setAlgebra03Expressions as a starting point.
You could use cotnextForm.pl, which relies on bizzarroArithmetic.pl:
https://github.com/Alex-Jordan/webwork-open-problem-library/blob/master/OpenProblemLibrary/macros/PCC/contextForm.pl