Translations:Appendix N: The energy-delay theorem/16/en

${\begin{aligned}\sum _{-\propto }^{N}{u_{n}^{2}}=\sum _{-\infty }^{N}{y_{n}^{2}}+\sum _{N+1}^{\infty }{v_{n}^{2}},\end{aligned}}$

(N8)