Ok. I feel a little dumb for asking, but I'm working on a abstract algebra proof and this has got me stuck:(adsbygoogle = window.adsbygoogle || []).push({});

[itex]\left(\sum_{i=1}^{n}a_ib_i\right)\left(\sum_{i=1}^{k}a_ib_i\right)[/itex] where n,k are some positive integers.

I feel certain that it's not just a sum to n+k or nk, but I could be wrong. any help would be awesome. :)

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# How to multiply these summations ?

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