Adding proof to questions?

Question

If there is a question and a previous answer is correct, but doesn't have proof, are we allowed to answer it with proof?

Comments

I'd suggest just giving a comment or something as a source, especially if it's a pretty simple question.

Answer 1

Like DT said, if the answer is correct then a comment would be a good idea just to verify it.

If the proof is quite long and detailed then a separate answer would be OK. As the rules state:

If someone else has already answered the question correctly there is no need to add another answer, unless you can add a lot more information.

In other words, if you can write a much better answer, then do it!