Kenneth Rosen Edition 7 Exercise 2.3 Question 36 (Page No. 154)

Question

Find $fog$ and $gof$. Where $f(x) = x^2+1$ and $g(x)= x+2$, are functions from $R$ to $R$.

Answer 1

1. fog(x) = f(g(x)) = f(x+2) = ((x+2)^2)+ 1 = x^2 +4x+5

2. gof(x) = g(f(x)) = g(x^2 +1)= (x^2 +1) +2 = x^2 +3