# composition of function

• February 28th 2009, 09:25 AM
14041471
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?
• February 28th 2009, 09:28 AM
red_dog
$(g\circ f)(x)=g(f(x))=g\left(\frac{1}{2x}\right)=3+\frac{1 }{2x}=\frac{6x+1}{2x}$
• February 28th 2009, 09:28 AM
skeeter
Quote:

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?

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