Expert: Ahmed Salami - 11/13/2008

Question
let f(x)=(1-x),g(x)=x/(x²-1) find fog and domin (f),domain (g) and domain (fog)

Answer
Hi Asma,
f(x)= 1 - x , g(x) = x/(x²-1)
fog = f[g(x)]
   = 1 - g(x)
   = 1 - [x/(x²-1)]
The domain of f is the set of all real numbers.
The domain of g is the set of all real numbers except when
x²-1 = 0
i.e x = -1 and 1
The domain of fog is the set of all real numbers except x = -1 and 1
(i.e the domain of g)

Regards