Functions Question 359
Question: If $ A={a,b,c,d},B={1,2,3}, $ which of the following sets of ordered pairs are not relations from A to B?
Options:
A) $ {(a,1),(a,3)} $
B) $ {(b,1),(c,2),(d,1)} $
C) $ {(a,2),(b,3),(3,b)} $
D) $ {(a,1),(b,2),(c,3)} $
Show Answer
Answer:
Correct Answer: C
Solution:
[c] $ {(a,1),(a,3)}\subseteq A\times B\therefore $ This is a relation. $ {(b,1),(c,2),(d,1)}\subseteq A\times B\therefore $ This is a relation. $ (3,b)\notin A\times B $
$ \therefore {(a,2),(b,3),(3,b)} $ is not a relation from A to B, $ (a,1)(b,2)(c,3) $ is a relation from A to B.
BETA
