\[u(r{\mathrm{e}}^{\mathrm{i}\theta})=\frac{1}{2\pi}\int^{2\pi}_{0}\frac{(R^{2}-%
r^{2})h(R{\mathrm{e}}^{\mathrm{i}\phi})\,\mathrm{d}\phi}{R^{2}-2Rr\cos\left(%
\phi-\theta\right)+r^{2}}\]