Formula_22358

\[x=\sum_{n=1}^{(s) / \infty} \frac{H_{n}}{k^{2}-n^{2} p^{2}} \sin \left(n p t+\delta_{n}\right)-\frac{H_{s}^{t}}{2 s p} \cos \left(n p t+\delta_{s}\right),\]