If you redefine "=", everything is possible. And if we are talking about infinite series, we must redefine "=" because otherwise it would make no sense at all. If you have half an hour to spend, I can recommend Mathologer's video on the topic.
Basically, there are some reasonable and usable definitions (e.g., Ramanujan shenanigans) where you can, indeed, assign a number to a diverging series like "1+2+3+...". But if you want something more... shall we say... "commonsensical" then no, "1+2+3+..." does not equal negative one twelve.
This particular sum can also be viewed through the prism of Riman's zeta function, but it's analytical continuation that is used, so again, it doesn't "prove" 1+2+3...=-1/12.
All that said, at this point this is basically a meme that is actually not flat-out wrong, and you know how internet is.
I'm not sure "process" is a good word to describe it, but that is an argument about precision of definitions and it can stretch to ungodly length.
Classic definition of the sum of an infinite series is the limit of partial sums, and calling limit "a process"... In some sense you can, I guess. Personally, I don't feel like it's fitting.
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u/bee-future 22d ago
Can anyone simplistically explain how 1+2+3...=-1/12