Often among young students, or those new to the site in general, we all see questions that are seemingly too trivial to even be asked. Usually, and perhaps unsurprisingly, these types of questions get closed nearly immediately.
I've been thinking about this a lot recently, and I'd like to explain why this hasn't been sitting well with me. I would also like to hear your thoughts too at the end.
I think the following question is a prime example. This will not be a protest to reopen said question, but rather an analysis of it as a question, how it was perceived, and the future of this site.
Is $1/\sinh(4x)$ equal to $\text{csch}(4x)$?
Sorry for the dumb question.
I do know that $\text{csch}(x)=1/\sinh(x)$, but I'm not sure if it applies to $x$ only. I don't know if it's applicable for $4x$ as well, or any other monomial.
"Sorry for the dumb question"
Although a tangent, I would like to point out that this quote, although appealing to emotion, emphasizes that the asker is aware of its triviality. The fact that users feel the need to apologize for their ignorance of a triviality on this site is probably not a good sign.
Lets talk about its triviality
To you and I, the average MathSE user, this question is very trivial. The asker (OP) is clearly in need of some foundational mathematical intuition, as pointed out by a commenter, when they responded to OP by saying
"I think you fundamentally misunderstand how to interpret mathematical identities. For example, (thing+1)-1=thing is true no matter what
thing
is, so you could say $(x+1)−1=x$ or you could say $(4x+1)−1=4x.$"
Clearly it's obvious what the asker is asking for, there's no issue there. It's a bit of a mystery to me why it was closed, but apparently not obvious to the minimum of 5 users needed to close a question. It seems like it was closed for being too trivial. Even if it weren't, that's how I perceived it.
Perhaps it was closed for lacking research, in which case, I ask this of you. Imagine you are someone with OP's level of mathematical understanding and terminology. What keywords do you search to answer your question?
You might notice, the issue with OP's question comes from a deeper misunderstanding of mathematical identities, rather than the specific nature of the hyperbolic trigonometric functions. A search engine is not going to pick up on this. Thus, their only resource for research is a Q&A site.
The problem
My problem is, trivialities are not trivial at all. For example, it takes months of direct immersion before we humans even understand the concept of object permanence. Plus, the problem of $$f(x)=g(x)\implies f(u(x))=g(u(x)).$$ (which is essentially the problem OP describes), is rather intensive to those first getting familiar with functions, domains, codomains, and ranges. The nature of the equals sign $=$ is even ambiguous. For example, if $f(x)=g(x)$, is this relation true for some solution $x$, or is this an equivalence relation between functions?
These are subtleties, and not trivialities. As I'm sure you're aware, there are so many subtleties in mathematics that one teacher could not cover them all. Hence, all students will eventually find one of these subtleties on their own, obfuscated by seeming triviality, and will have no where else to go, except for a question and answer site such as this one.
From of business point of view, the chances of this user coming back to this site after having their question closed is likely eviscerated due to the psychological consequences of having their thoughts being perceived and deemed too trivial.
This was just one example, of the potentially thousands of unique questions with a similar story. It got closed for not meeting the guidelines, not for being a duplicate.
From my eyes, it is our duty on Math.SE to be an encyclopedia of mathematical questions and answers. Why should we prohibit explaining the subtleties?