I want to know the answer of an already posted question. I did this(following link) and supposedly I was wrong. What to do?
Given that you are not OP of the original question, but one of the providers of the two incompatible answers (which both turned out to be wrong), the proper thing to do would seem be: to scrutinise your answer, compare it to the other one, maybe add some explanation to your answer to make it clearer that your answer must be the right one (or find out why it isn't right in trying to do so; this often happens). Normally you will get the attention of OP just by providing or modifying your answer; in a desperate case you could add comments to ask whether your answer is considered correct by OP, and if not why not (I think you just have enough credit now to do that; probably you did not at the time though). Anyway, asking a separate question to the effect of "please tell me if my answer on that other question is correct" is not a proper thing to do.