# Composition of functions (in set)

1. May 13, 2009

### 385sk117

1. The problem statement, all variables and given/known data

A = {0, 1, 2, 3} f and g are fucntions mapping A to A where
f = {(0,1),(1,2),(2,0),(3,3)} and g = {(0,2),(1,3),(2,0),(3,1)}
find

(f o g)(1)

2. Relevant equations

3. The attempt at a solution

The answer is 3 but i can not get it..
the (1) on the right side means find the y value whem x = 1
I think my (f o g) thing is not correct but i dont know how to do this..
book just gave me an example but that is totally different from this one.

2. May 13, 2009

### Cyosis

You know that $(f \circ g)(x)=f(g(x))$?. Can you tell us what value g(1) has?

Last edited: May 13, 2009
3. May 13, 2009

### 385sk117

g(1) would be 3 as g has point (1,3)

4. May 13, 2009

### 385sk117

Ohh i got it.
g(1) is 3 and as f has point (3,3) the answer is 3
thanks!

5. May 13, 2009

### Cyosis

Yep that is correct. Now what is the value of f(3)?

Edit: Seems you beat me to it! Yes that's all correct.