I think the question is now perfectly acceptable, and I personally would vote to reopen it.
That being said, it's not very good for the community moderation model if I go around closing and opening things willy-nilly. Your question was reviewed twice since you edited it (first review, second review, and all four reviewers thought it was still inappropriate for the site. We should find out why. Hopefully at least one of them stops by to provide an answer (and I'll see if I can bug them about it).
Should I simply delete the post and then create a duplicate?
No, don't do that. Deleting and reposting questions is against our rules (of course as a new member, you probably wouldn't have known). If further edits are required, you can just keep editing the same question. Just try to batch up your edits so that you make all the changes required at once, and that you don't wind up editing the post too many times.
There are a few edits you could make to your question that would vastly improve it, and even though these shouldn't be the cause for it to stay on hold, given human nature, these might help the question's chances:
- Don't post a screenshot of text from a book. Instead, retype the relevant parts of the text, making sure to use a quote block to indicate what you have copied from the book. (Make sure to acknowledge the source, too.)
- Improve the math formatting by using the operator macros
\cos, and writing kets as
\lvert jm\rangle instead of
Perhaps most important, give your question a better title. Even though the decision to put a question on hold should be based on the body, not the title, whatever title you do choose is your question's first impression to readers and it can influence their judgement of the body.
In your case, "SU(2) Rotation Matrices Problem from Halzen and Martin" says nothing about what you're actually asking. Besides, the key word in the title is "Problem", which suggests that you want the solution to the problem from the book, even though that's not what you're actually asking in the body. A better title would highlight the conceptual issue you're actually asking about. Based on your wording in the body, you could go with something like "How can one obtain the eigenvalues of a rotated higher spin system?", or if you want it shorter, "Eigenvalues of a rotated higher spin system". (Titles don't have to be questions, though in my experience it's often easier to write a good title if you make it a question.)