Which ordered pairs xy are in the relation x y 1 from the
Which ordered pairs (x,y) are in the relation (x > y + 1) from the set {1,2,3,4}?
Solution
For (x,y) to be in the relation we need to first look at the set:y+1 ={2,3,4} ie y+1 can take these three values
x needs to be larger than this
Corresponding to 2 x can be 3 or 4
2=y+1 so , y=1
So, (2,1),(3,1) is in the relation
Corresponding to 3
x can be 4, y+1=3 so y=2
So ,(4,2) is in the relation
Corresponding to 4 there is on x. So only these three ordered pairs are in the relation

