I asked this question sometime ago and had no idea how to solve it. Later, I got a hint(the first answer there) and used it to reach a conclusion, which I then wrote in the comments. The person who gave the hint confirmed the answer was correct and I let the matter be. Sometime later, I remembered it, out of nowhere, and realized that my reasoning could have been wrong. So, I posted an answer and thought somebody would tell me whether it is correct(possibly the original hint-giver). But, I got none. What do I do in such circumstances when I want my reasoning(not more than 3-4 steps) glanced at, by an expert?
Answerers don't get notified when other answers are posted. If you didn't post a comment below the hint saying that you'd posted a self-answer, the person who wrote the hint will not know you did that.
However, this isn't really what Stack Exchange is for. The expectation is that answers are believed to be correct by the person who posted them. Answers are taken as meaning, "To the best of my ability, this is the solution to the problem at the top of the page" not "Could you please tell me if this is right?" The latter is a question, not an answer.
You should probably ask a question.
You know, of course, that there are two main ways to contribute to any Stack Exchange site: asking questions and posting answers. When people ask questions, they are seeking knowledge from others, and when people answer questions, they are offering knowledge. The entire design of the site is made to facilitate that flow of information from answerers to askers, but it doesn't work quite so well going in an opposite direction. So if you want feedback on something, it's best if you do so in the form of a question, even if the thing you are asking about happens to be an answer to another question.
If your question wouldn't be appropriate on the site, you could try bringing it up in chat.