If I have a question that depends on a previous question that's already resolved, how do I post that follow up Question?
- Edit my original question
- Post a new one
If I have a question that depends on a previous question that's already resolved, how do I post that follow up Question?
Post a new question, linking back to the original with a brief explanation of how they are connected.
Editing the old question is bad form, as it would require the existing answers to be re-written (which is a pain for those kind people who took the time to answer the question!).
There are, of course, exceptions. The main one, as has been pointed out in the comments, is when "there is a trivial case you forgot to rule out (such as the function is identically zero) and the answer is merely that trivial case. Then, feel free to orphan the trite answer by improving your question."
The key points here, thought, are that the case should be trivial and the answer should be trite. For example, The OP of this question omitted a non-trivial case, and the answer was simple but pleasing (it was not trite$^{\dagger}$). So the OP started a new question rather than editing the original.
$^{\dagger}$ Trite (adj.): (of a remark or idea) lacking originality or freshness; dull on account of overuse.