Assuming that you are the author of the original question and you feel as though you have made progress due to the answers given, but you are not satisfied or you have not reached the mathematical equation you aspired to achieve, would it be appropriate to replace the existing question with your new, highly-related one? For example, you are stuck on a specific part of an algorithm. Somebody makes a helpful post and you modify your algorithm. You get most it worked out. Your original question might have been something like "how do I do this algorithm?" and now your question is "how do I implement or fix part A of this algorithm?". It's not exactly the same question, really, but it is part of the process of finding the correct answer to the original question.
So, would it be acceptable to replace your question, A, with a highly-related question, B, which still deals with the same problem in some way or another?