1. Function Composition.

Trying to work out the answer to the following:

Let f1 and f2 be two functions from N to N such that:
f1(x) = x^2 and f2(x) = 3x + 6x^2.

Question 1) What is the function f1 ∘ f2?
Question 2) What is the function f2 ∘ f1?

I am very confused by function composition and any help would be greatly appreciated!

Thanks!

2. Re: Function Composition - help needed!

Replace the whole function for x, so

$\displaystyle f_1(f_2(x)) = (f_2(x))^2 = (3x + 6x^2)^2$

Finish it off.

3. Re: Function Composition

Originally Posted by pickslides
Replace the whole function for x, so

$\displaystyle f_1(f_2(x)) = (f_2(x))^2 = (3x + 6x^2)^2$

Finish it off.
Thank You ever so much