[tex](adsbygoogle = window.adsbygoogle || []).push({});

\begin{array}{l}

\delta _{jk} A_k \\

\\

\delta _{jk} A_k = \left( {\delta _{1,1} + \delta _{1,2} + \delta _{1,3} + \delta _{2,1} + \delta _{2,2} + \delta _{2,3} + \delta _{3,1} + \delta _{3,2} + \delta _{3,3} } \right)A_k \\

\,\,\,\,\,\,\,\,\,\,\,\,\, = \left( {1 + 0 + 0 + 0 + 1 + 0 + 0 + 0 + 1} \right)A_k \\

\,\,\,\,\,\,\,\,\,\,\,\,\, = 3A_k \\

\end{array}

[/tex]

But the answer should be [tex]A_j[/tex]. Where did I go wrong?

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# Homework Help: Kronecker delta symbol

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