Is it possible to represent the dot product (matrix multiplication) with sums? For example, know the dot product of a polynomial and another one [i.e. 2+5x and 3x+7x(adsbygoogle = window.adsbygoogle || []).push({}); ^{2}] would be the sums of the products. [i.e. 2(3x) + 5x(7x_{2})].

Could this be also written as [tex]\sum^{n}_{i=1}[/tex] a_{1i}b_{i1}? I'm asking this because I'm taking a really strict teacher who wants you to show all your work on a test or else he marks the entire thing wrong and showing the work for a dot product of a 5x2 by 2x5 is too much work during a timed exam.

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# Representing a dot product with Sums.

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