in this question I asked a specific concept and I have shown all my works and efforts behind it even though it was closed.
I just want to know where am I going wrong.
see this question
and more over i think that i am just asking a mathematical concept that which step would the particle hit.
so according to this post on meta.physics.stackexchange.com
Ask about the specific concept that gives you trouble
We expect you to narrow down the problem to the particular concept that's giving you trouble and ask about that specifically. That produces a question that is more relevant to others who might be having the same problem, as well as probably more interesting to answer. As a side effect it shows that you're not just being lazy and trying to get us to do your work for you.
The best way to produce a focused, specific question is to show your work. Explain what you've been able to figure out so far and how you did it. Showing your work will help us gauge where you are having problems: if it is a technical thing near the end, a short to the point answer will suffice; if it is some fundamental problem with understanding the subject, somebody will then write a longer, more detailed response. It will also prevent people from spending a lot of time going over ground that you have already covered or understand well already.