Functions

[lewch45]

I need help on one more. With this I need to find g o f and f o g for the given functions f and g.

f(x)= square root x + 4, g(x)= 1/x

I started to so the problem but then I got stuck. Any help would be appreciated. Thanks.

 

[stapel]

I started to so the problem but then I got stuck.

We'll be glad to help you get un-stuck. Just post whatever you've done so far, and we'll see what we can suggest to get you going again.

Thank you!

Eliz.

 

[lewch45]

Here's what I've got so far:

(g o f )= g [f(x)]= 1/ (f(x))= 1/ square root x + 4

(f o g )= f[g(x)]= square root g(x) +4= square root 1/x+4

I have no idea where to go from here. Any help please?

 

[Gene]

You can use more ()s to show grouping. I guess
f(x)= sqrt(x + 4), g(x)= 1/x

(g o f )= g [f(x)]= 1/ (f(x))= 1/ sqrt(x + 4)
Looks good to me unless you are supposed to go on to
= sqrt(x + 4)/(x+4)

(f o g )= f[g(x)]= sqrt g(x) +4= sqrt (1/x+4)
Looks good too. What else are you supposed to do?

 

[lewch45]

I'm not sure if I need anything else besides that. In my original post I wrote exactly what the instructions said. I guess that's good. Thanks for your help!!