Question

What is the difference between domain and co-domain?

Answer 1

http://www.mathsisfun.com/sets/domain-range-codomain.html

Answer 2

First of domain is the X set and co-domain is the Y set

Answer 3

In f(x)=2x+1, we say that it's f:Z->Z

Answer 4

So Z is the domain and Z is the co-domain

Answer 5

But the range is all odd numbers bigger than 2

Answer 6

What can go into a function is called the Domain
What may possibly come out of a function is called the Codomain
What actually comes out of a function is called the Range

Answer 7

So a co-domain is basically the range?

Answer 8

They're similar

Answer 9

What may possibly come out of a function is called the Codomain
What actually comes out of a function is called the Range

Answer 10

What do you mean by 'come out of a function'?

Answer 11

That means the value of Y

Answer 12

http://www.mathsisfun.com/sets/images/domain-range-codomain.gif

Answer 13

Domain is 1~4, co-domain is 1~10, range is {3,5,7,9}

Answer 14

SO it is pretty much the range?

Answer 15

It has a bigger range than the range (confusing pun intended)

Answer 16

What is the difference?

Answer 17

Sometimes they're the same

Answer 18

Look at the picture

Answer 19

For example in f(x)=2x+1, if f:R->R, then the co-domain and the range are the same

Answer 20

But if you're talking about f:Z->Z then the range is smaller than the co-domain

Answer 21

So how do you figure out the co-domain?

Answer 22

You could say that f:Z->C and the co-domain would be C

Answer 23

You define the co-domain

Answer 24

Actually I'm not so sure so @Hero @phi

Answer 25

This was in that web page you suggested:
Example: you can define a function f(x)=2x with a domain and codomain of integers (because you say so).
But by thinking about it you can see that the range (actual output values) would be just the even integers.
So the codomain is integers (you defined it that way), but the range is even integers.

Answer 26

Yep that's what I mean

Answer 27

But it is wrong.

Answer 28

No integers are possible in this graph.

Answer 29

non*