I dont understand how you can tell its a function or not

[Eva Barragan]

The directions say find the domain and range of each relation. Is the relation a function.
The problem is: {(4,1),(7,1),(-2,4),(1,1)

I allready found the range and the domain
DOMAIN:4,-2,1
RANGE:1,4,1


but how do you know if its a function

 

[Guest]

look up the definitions for domain and range

~Ainsley~ :twisted:

 

[Gene]

If, for every X in the domain there is exactly one y, it is a function.

 

[Eva Barragan]

hey ainsley! hi gene!
sorry it has taken me so long to reply i havent been on this website in a while
thanks alot for your help really appreciate it.
ummm gene i dont get what you mean with this: for every x in the domain there is exactly one y?
thanx for ur help
both of you

 

[Gene]

Hmmmm, well
y=x^2
The domain is all real x's. For any x you put in you get exactly one y. It is a function.
y=+sqrt(x) The domain is all positive x's but for each x you get two y's. It is not a function.

 

[Eva Barragan]

thanx gene that does help ill try to remember that
-thanx