# Math Help - composition of function

1. ## composition of function

If f(x) = 1/(2x) and g(x) = 3+x find (and simplify) the defining equation of the composition function g \circle f .

I don't have any idea how to combine these two functions, can anyone help?

2. $(g\circ f)(x)=g(f(x))=g\left(\frac{1}{2x}\right)=3+\frac{1 }{2x}=\frac{6x+1}{2x}$

3. Originally Posted by 14041471
If f(x) = 1/(2x) and g(x) = 3+x find (and simplify) the defining equation of the composition function g \circle f .

I don't have any idea how to combine these two functions, can anyone help?
$g[f(x)] = g\left[\frac{1}{2x}\right] = 3 + \frac{1}{2x} = \frac{6x+1}{2x}$