Hello Chris
thanks a lot for that. We have temporarily settled for a workaround to ask the student explicitly to include the constant of integration; but your change will be much appreciated once we update our Moodle code!
It's good to know that the absolute value check can be influenced via the teacher's answer. I was particularly concerned about changing all the example questions on integration of partial fractions... but adding an "assume(v>100);" to the question variables sorted the issue for us in most cases (forcing the model answer not to include absolute values), so it was easier than I thought it would be.
Thanks again
Henning