9. Let C be the set of professors in a mathematics department who taught a calculus class and D the set of professors in a mathematics department who taught a discrete mathematics course. Describe each of the following sets in terms of C and D. (a) the set of professors in the mathematics department who taught both a calculus course and a discrete mathematics course. (b) the set of professors in the mathematics department who taught either a calculus course or a discrete mathematics course. (c) the set of professors in the mathematics department who taught neither a calculus course nor a discrete mathematics course. (d) the set of professors in the mathematics department who taught a calculus course but not a discrete mathematics course.

Fig: 1