Translations:Causality and stability of digital systems/6/es

${\begin{aligned}h_{k}=0\mathrm {\;} \;\;\;\;{\rm {for}}\;\;\;\;k=-{\rm {l,}}-{2,}\ldots \\h_{k}=a^{k}\mathrm {\;} \;\;\;{\rm {for}}\;\;\;\;k=0,1,2,\ldots .\end{aligned}}$

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