Formula_1109

\[\begin{gathered}u(x, t)=t^{-1 / 2} A(s) \exp \left\{i t\left[s^{2}-2 A^{2}(s) \frac{\ln t}{t}+\frac{\phi(s)}{t}\right]\right\}+ \\+O\left(t^{-3 / 2} \ln t\right), \quad t \rightarrow \infty,\end{gathered}\]