(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Consider any sequence a_{1}, a_{2},..., a_{n}and the nxn array of values b_{ij}= a_{i}a_{j}. Which terms in the array are involved in the sums L = Ʃ(between i=1 and n)Ʃ(between j=1 and i) b_{ij}

and U = Ʃ(between j=1 and n)Ʃ(between i=1 and j) b_{ij}?

Also, by symmetry, show that L=U.

2. Relevant equations

n/a

3. The attempt at a solution

I've just started this topic and the double summation is really confusing me. Any guidance or suggestions on how to approach this would be really useful thanks.

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# Double summation problems

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