Answer
a) (a,b) where student a is required to read book b OR has read book b
b) (a,b) where student a is required to read book b AND has read book b
c) (a,b) where student a either is required to read book b, but haven't read it OR has read book b but is not required for the class.
d) (a,b) where student a is required to read book b but haven't yet
e) (a,b) where student a has read book b but isn't required for the class.
Work Step by Step
a) It is the union of R1 and R2 so, it could be R1 or R2 or both. (inclusive or)
b) It is asking for the intersection of R1 and R2, so it would be pairs who are in both R1 and R2.
c) It is like number a but it is an EXCLUSIVE or, that means that (a,b) can't be in both R1 and R2.
d) It is (a,b) that is in R1 but not R2.
e) It is (a,b) that is in R2 but not R1.
