Question

OLLEGE

Answer 1

Part 1

$(f\circ g)(x)=f(\sqrt{x})=4\sqrt{x}+1$

We need to make sure the radical is defined, meaning the radicand has to be non-negative. Thus, the domain is $\boxed{[0, \infty)}$

Part 2

$(g \circ f)(x)=g(4x+1)=\sqrt{4x+1}$

We need to make sure the radical is defined, meaning the radicand has to be non-negative. Thus,

$4x+1 \geq 0\\\\4x \geq -1\\\\x \geq -\frac{1}{4}$

Thus, the domain in interval notation is $\boxed{\left[-\frac{1}{4}, \infty)}$