My question was about derivatives, and I thought it was a good question.
But then, Moderators put my question [on hold] saying that it was off-topic. Now, I am wondering why it was an off-topic post. Can you explain?
I do not understand your question. It said this on the page:
"This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." –
Apparently you understood this and followed up on it, which is good. Now you have to wait if the post gets reopened. If you want to know why it did not yet get reopened, then you should ask about this. Why it was put "on hold" in the first place is pretty well-documented though.