I had a [long discussion in chat](https://chat.stackexchange.com/rooms/98964/discussion-between-xander-henderson-and-6005) over what seems like a simple question:

> 
> Is $\sin \infty$ an [indeterminate form](https://en.wikipedia.org/wiki/Indeterminate_form)?
> 
> 
> 

What do you think? :)

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I'm labelling this as `(soft-question)` to be safe, but it should have a clear answer depending on the definition of *indeterminate form* used.
The term "indeterminate form" is seldom used in post-calculus mathematics, but I believe it has one or more accepted definitions, which are either informal or formal. So any answer which takes a standard definition and argues the case would be interesting to me.

**How to make a good answer:**

1. State the definition of indeterminate form, either from an online or textbook source, or a definition you came up with on your own.
2. Determine, using your stated definition, whether $\sin \infty$ is indeterminate or not.

**EDIT: What do I mean by $\sin (\infty)$?**

It's not a well-defined expression, but neither are any of the other indeterminate forms: $\frac{0}{0}$ doesn't exist, $1^\infty$, doesn't exist, and so on. So the question is whether this expression -- *which is not well-defined, just like any other indeterminate form* -- is an indeterminate form.