You have to provide methods for returning output strings in fully
parenthesized infix and postfix forms according to the above
convention. Note that if you blindly apply the rules
for differentiation, you may get
which is correct but somewhat unsatisfactory. You will get
extra credit if you can program the rules for ,
, , , ,
and so on. The more simplified the output is
the more credit you will get.
In particular, you will get
bonus if you can provide methods for checking equality
of expressions. This will require you to reduce your expressions
to a suitable normal form.