## kymber 3 years ago How to do composition of functions?

1. amorfide

could you give a question as an example

2. kymber

der you go

3. amorfide

okay so you have f(x)=2x-1 g(x)=x+2 so you want gf this means you will do g(f) so your g function is g(x)=x+2 now g(f)=f+2 because it replaces all the x's but you know that f(x)=2x-1 so you are doing g(f) which is equal to g(2x-1) so your g function is g(x)=x+2 instead of x you will replace all x's with 2x-1 so g(2x-1)=2x-1+2 g(2x-1)=2x+1

4. kymber

So composition is just multiplying??

5. amorfide

no you had gf that is a function of f but you know that f is 2x-1 so you sub that into your function for g you are replacing the function on the right with its function of x then the substituting it into the function that follows the one on the right like here the function the right is f which is 2x-1 you subbed that into the function for g

6. kymber

So composition is putting f into g?

7. amorfide

yes

8. kymber

Oh.. okay. Thanks \(\huge\ddot\smile\)

9. amorfide

if it makes it easier to understand try this you have gf you could re write it to be gf(x) you know f(x)=2x-1 so you can rewrite it to be g(2x-1) sub it into the g function