# Function and relations

1. Feb 7, 2014

### nae99

If f(x)= 2x+5, g(x)=0.5 and h(x)=3-1
find:
fg(x), gf(x), fh(3)

fg(x)
fg(x)= 2(0.5x)+5
fg(x)= x+5

gf(x)= 0.5(2x+5)
= x+2.5

fh(3)
fh (x) =2(3-1)+5
= 6-2+5
= 4+5

this last part of the question been puzzling me... could I get a little help plzzz

2. Feb 7, 2014

### Dick

I'm going to guess from your solution you meant g(x)=0.5*x. If you really meant h(x)=3-1 then the last one is fine. But writing h(x)=3-1 is a little odd. Why not just write h(x)=2, or is it another typo?

Last edited: Feb 7, 2014
3. Feb 9, 2014

### eumyang

Isn't the notation wrong? It looks like you want
$(f \circ g)(x)$, $(g \circ f)(x)$ and $(f \circ h)(x)$
(function composition)
but it looks more like
$(fg)(x)$, $(gf)(x)$ and $(fh)(x)$
(combining functions by multiplication)