# Closing as duplicate of blog post

Again there was a question about what $dx$ is. I know that this question has been up several times and that there has been a bit of disagreement on how to best answer the question. The natural thing, of course, is to close this as a duplicate of one of the other such questions.

Fortunately though Robin Goodfellow wrote a blog post giving a nice answer. Therefore I was wondering if it would make sense if it was possible to close a question as a duplicate of a blog post.

• The blogs run on a Wordpress installation and are not really integrated into the SE platform. The whole blog idea is on hold until it can be integrated better and be generally improved, so I strongly doubt that SE would change something like this. – user9733 Dec 16 '14 at 13:10
• @MadScientist: Ok. I didn't know that. – Thomas Dec 16 '14 at 13:40
• One possibility is to create a custom "off topic" close reason in the interim. (I'm not advocating that, but it's an option.) – apnorton Dec 16 '14 at 15:53
• How about answering one of the existing questions with a reference to and quotes from the blog post? – Isaac Dec 16 '14 at 18:56

Second, I think this is not a desirable feature. One of fundamental principles of SE is that everyone can answer a given (non-closed) question, and the best answers rise to the top; additionally, the question author is able to select one answer as most helpful. None of this is available on a blog. Robin's explanation of differential forms on manifolds may be great, but a calculus student confused by $\Delta x$ and $dx$ in "thin slice" integration problems might find it hard to follow, especially since they likely had no multivariable calculus yet. On a Q&A site, there could be other, more accessible answers. Not on a blog.
Indeed, my blog post was mostly me venting after reading a string of "differential geometry" questions that should have just been filed under multivariate calculus. It was certainly not meant for students just starting calculus. For a new student, I would suggest introducing $\mathrm{d}x$ simply as a special kind of vector that is, in some sense, complementary to the derivative operator $\frac{d}{dx}$. I would probably avoid delving deeper into this definition with the student until (at least) they understand the concept of directional derivatives.