Let \(U\) be the open unit disc in \(\mathbb C\). Let \(U^+\) be the intersection of \(U\) with the upper half plane.
(a) Let \(f(z)=\frac {1}{2}\left (z+\frac {1}{z}\right )\). Describe \(f(U^+)\).
(b) Give a conformal equivalence of \(U^+\) and \(U\).