Solution
= Solution
Use the principal branch $\operatorname{Log}z=\log|z|+i\arg z$, with $-\pi<\arg z<\pi$. Then
$$
\boxed{f(z)=i\operatorname{Log}z=-\arg z+i\log|z|}
$$
is a <conformal equivalence> from the slit plane to the vertical strip. Its imaginary part tends to $-\infty$ as $z\to0$ and to $+\infty$ as $z\to\infty$.