What to do when someone ask for a mistake, comment indicating where he made the mistake or answer indicating where he made the mistake?

For example, someone ask about a limit that he knows the solution but he get another solution doing himself, then he makes a question posting the steps he made for getting his solution and asking where he made a mistake.

When someone finds that mistake what should he do, comment or answer?

What to do when someone ask for a mistake, comment indicating where he made the mistake or answer indicating where he made the mistake?

If what they seek is the mistake, and you wish to state what that mistake is, I would post that as an answer - preferably with an analysis of why this is a mistake, and perhaps a hint or nudge at how to correct it if the situation allows.

• What if there is no mistake to be found and everything is perfect. Should one just write an answer like: "Yes, your method is correct." ? – Three Sided Coin Feb 13 '19 at 1:01
• I don't see why not. – Eevee Trainer Feb 13 '19 at 1:45
• @Zacky Here are some previous discussions related to your question: What's the policy on answering a question where the correct answer is simply “yes”? and How to answer proof-verification questions? – Martin Sleziak Feb 13 '19 at 6:32
• But imagine the mistake is just for example a wrong calculation such 2+2=5. Then you should just answer “you made a mistake when doing 2+2”? – JoseSquare Feb 13 '19 at 8:52
• "Then you should just answer “you made a mistake when doing 2+2”?" - I don't see why the triviality of the mistake would have a bearing on the matter. That is to say, yes, that should be your answer IMO. – Eevee Trainer Feb 13 '19 at 23:44

I think the confusion that there are two questions:

• the maths problem
• "Where did I go wrong?"