Question

If f(x)=x and g(x)=x+1 find the function and its domain:

1. gof

2. fof

Answer 1

(gof)(x) means you substitute the whole expression of f(x) to g(x):
(gof)(x) = g(f(x)) = f(x) + 1
(gof)(x) = x + 1

for #2, we do the same,, we substitute f(x) to f(x):
(fof)(x) = f(x)
(fof)(x) = x

hope this helps~ :)

Answer 2

Sweet! Thanks