Answer
$a.\qquad 2\sqrt{2}$
$b.\qquad 2\sqrt{2}$
$c.\qquad 1$
$d.\qquad 0$
Work Step by Step
$a.$
$(f\circ g)(4)=f[g(4)]$
$g(4)=2(4)=8$
$f[g(4)]=f(8)=\sqrt{8}=2\sqrt{2}$
$b.$
$(g\circ f)(2)=g[f(2)] $
$f(2)=\sqrt{2}$
$g[f(2)] =g(\sqrt{2})=2\sqrt{2}$
$c.$
$(f\circ f)(1) =f[f(1)]$
$f(1)=\sqrt{1}=1$
$f[f(1)]=f(1)=1$
$d.$
$(g\circ g)(0)=g[g(0)]$
$g(0) =2(0) =0$
$g[g(0)]=g(0)=0$
