I stumbled upon this expression:$$p_nq_mx^{m+n}+(p_{n-1}q_m+p_nq_{m-1})x^{m+n-1}+(p_{n-2}q_m+p_{n-1}q_{m-1}+p_nq_{m-2})x^{m+n-2}+\ldots+p_0q_0\tag1$$ And I'm wondering if there is an easier way to represent $(1)$ using the sum notation Sigma: $\sum$.
How would you write this in Sigma notation
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$\begingroup$
summation
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0Are you sure the last term $p_0q_0$ is correct? It doesn't seem to match up with the rest. – 2017-01-20
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0@AlexR. Yes, I'm $100\%$ sure... – 2017-01-20
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0sure it does, $x^{0+0}=1$ – 2017-01-20
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0That would be the $x^m$ term which is somewhere in the middle. – 2017-01-20
1 Answers
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$$\sum_{i=0}^{n}\sum_{j=0}^{m} p_iq_jx^{i+j}$$
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0Cool, good enough! Thanks! – 2017-01-20