@Peter The “no longer needed (outdated, conversational or not relevant to this post)” flag would be suited for comments which are apparently posted as a joke. But the question itself is deleted now, so there is (IMO) no need for action anymore.
Sorry, got to really fast , conference call! For the past two days I haven't spent more than 5 minutes in a row and half an hour in total on the site. i hope the trouble will end soon!
This is probably a duplicate I would like to consider this as the duplicate target, but I'm not a cent percent sure. If someone confirms it, I'm going to close as well.
For the above, it seems that a source would be perfect context. I think integral solvers should use approach0 a lot more : it throws up so many techniques and related examples that could make one's day.
@Christoph Not quite : there's a difference between having the $4n^2-1$ and the $4n^2+1$ : which throws the antiderivative and the series expansion approaches out. One can attempt Felix Marin's approach but it's certainly not the same, I think.
No worries. I already spotted this sister integral on Approach0 so it was good I saw the difference earlier. From what I see, the question is harder when it's +1, but you can still do it if you get the right antiderivative.
Like I just did : sin(nx)e^{-x} is the correct kind of function to look for.
Then you can use an interchange of integral and sum, and finally put the geometric series together and integrate back. It's beautiful, but I'm not touching that until I see it's improved.
@vitamind Yes. It's a very poor question, and the answerer, for answer a vlq question, really should not earn +100 for doing so.
@vitamind No need to delete at this point. It's only a question. If closed before receiving an answer, we can allow the user time to improve it, without risk of an answerer.
Honestly I'm pretty mad about that one. Right as I was typing a comment linking to "How to ask a good question" someone posted a full answer admitting "even this question does not fit on MSE".
