Is it possible to use sigma notation for non-integer steps, for example I want to sum $\ln(x)^2$ from $2$ to $20$ with steps of $0.5$, is there a way I could write this in sigma notation or some other form of notation.
[Math] Sigma notation for sum of $\ln(x)^2$ from $2$ to $20$ with non-integer steps
notationsummation
Best Answer
In this particular case that you have the constant difference, I would go with the other answers; it's the simplest and most non-confusing manner to write what you want to convey. However, if you have any arbitrary set $S$, and wanted to sum based on its elements, you can write something like $$\sum_{s\in S}f(s).$$ In particular you might have $S=\{2,2.5,3,\dots,20\}$.