I have a question, wish learning, and need help :
Thanks in advance for time and help.
and small extension with the above :
A sum from n=1 to n makes no sense. Do you mean a sum from n=1 to N (and on the RHS also replace n with N)?
Many thanks for your help, Richard. Yes, I mean :
And by modern convention then :
and a bit of editing for the above :
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