for some reason the nullspace(M) function doesn't work for me anymore. The questions I wrote two years ago still work fine. But when I try to build a new question, the span of any given Matrix is always empty.
I tried to run the function in wxMaxima which works fine, as long as I don't compile the STACK sandbox-file. In that case nullspace() is also an empty list. (Same happens, if I copy the questionVariables of one of the old, working questions in the Sandbox...)
Is there anything I can do, besides writing a new function?
Thanks a lot,