Answer
$f(x)=\sqrt x$ and $g(x)=1-x^2$
Work Step by Step
We wish to find two functions $f$ and $g$ such that:
$H(x)=(f \circ g)(x) =\sqrt {1-x^2}$
Let us consider:
$f(x)=\sqrt x$ and $g(x)=1-x^2$
Then we have the composite function:
$H(x)=(f \circ g)(x) =f[g(x)]=f(1-x^2)=\sqrt {1-x^2}$
