Chapter 12 - Exponential Functions and Logarithmic Functions - 12.1 Composite Functions and Inverse Functions - 12.1 Exercise Set - Page 787: 15

$a.\quad(f\circ g)(1) = 2$ $b.\quad(g\circ f)(1) = 4$ $c.\quad (f\circ g)(x) = \sqrt{x+3}$ $d.\quad (g\circ f)(x) = \sqrt{x}+3$

$(f\circ g)(x)=f[g(x)]=\sqrt{g(x)}$ $= \sqrt{x+3} \qquad ... \quad(c)$ $(f\circ g)(1)=\sqrt{1+3}=2 \qquad ... \quad(a)$ $(g\circ f)(x)=g[f(x)]=[f(x)]+3$ $= \sqrt{x}+3 \qquad ... \quad(d)$ $(g\circ f)(1)=\sqrt{1}+3=4 \qquad ... \quad(b)$