Expert: Paul Klarreich - 2/14/2008

Question
having problems answering this question. Task Determin whether each relation is a function. In addition, provide reasons for identifying
a relation as a function.
1. (3, 4), (5, 9), (9, 9), (2, 3)
2. (0, 0), (0, 1), (1, 4), (2, 4)
3. (2, 1), (4, 5), (8, 4), (1, 0)
4. (8, 3), (8, 0), (7, 7), (4, 7)

Answer
Questioner:   juan lopez
Category:  Advanced Math
Private:  No
 
Subject:  algebra
Question:  having problems answering this question. Task Determin whether each relation is a function. In addition, provide reasons for identifying
a relation as a function.
1. (3, 4), (5, 9), (9, 9), (2, 3)
2. (0, 0), (0, 1), (1, 4), (2, 4)
3. (2, 1), (4, 5), (8, 4), (1, 0)
4. (8, 3), (8, 0), (7, 7), (4, 7)
......................................
Hi, Juan,

Step 1: Read the definitions over again.  And over again. And make sure you understand what all the words mean.  

Step 2: Repeat Step 1.

Now here are your definitions:

A RELATION is any set of ordered pairs.
A FUNCTION is a relation in which NO TWO ordered pairs have the same first number.

So look at each set of ordered pairs.(each of your 1,2,3,4 is a separate example.)

If you find two ordered pairs with the same first number, say:

NO, IT'S NOT A FUNCTION BECAUSE I see (?,?) and (?,?) with the same first number. [You fill in the ?'s]

[You don't just say two o.p's have the same f.n.  -- you have to be specific and name them.]

If you can't, say:

YES, It's a function because every ordered pair has a different first number.