Formula_1102

\[\tilde{u}(x, \hat{k})=e^{i \hat{k} x}-\frac{1}{4 \pi} \int_{\mathbb{R}^{3}} \frac{e^{i k|x-y|}}{|x-y|} V(y) \tilde{u}(y, \hat{k}) d y\]