Let r1 and r2 be the "divides" and "is a multiple of" relations on the set of all positive integers, respectively. thatis, r1 ={(a, b)|adividesb}andr2 ={(a, b)|a is a multiple of b}. find

a. r1 ∪r2.

b. r1 ∩r2.

c. r1 −r2. d)r2−r1. e)r ⊕r. 1 2