# Composite Functions

1. Sep 18, 2009

### Larrytsai

f o g (x) = Abs(x)
f(x)=?
g(x)= root(x)

im thinking f(x) is = to root(x) correct me if im wrong?

2. Sep 18, 2009

### Staff: Mentor

f(x) = sqrt(x) doesn't work. Are you sure you have this problem written correctly? Could it be g o f (x) = Abs(x)? That would make more sense with g(x) being sqrt(x). Of if it is indeed f o g (x) = Abs(x), could it be that f(x) = sqrt(x) and you need to find g(x)?

3. Sep 18, 2009

### Larrytsai

its correct way i took it straight from the book.

4. Sep 18, 2009

### Staff: Mentor

OK.
If f(x) = x2 and g(x) = $$\sqrt{x}$$
then $(f~\circ~g )(x) = x$.

Since the domain of g = {x | x $\geq$ 0}, then x = |x| in this case.