Solution
= Solution
The <continuous function>
$$
\boxed{f(x)=\frac1x-1\qquad(0<x\leq1)}
$$
has the required image. Its values are nonnegative, and for every $y\geq0$ the point $x=1/(y+1)\in(0,1]$ satisfies $f(x)=y$. Thus the image is exactly $[0,\infty)$. The missing left endpoint permits unboundedness without a failure of <continuity> on the domain.