## Hyperbolic sine, shine or sinsh (or sinch)?

An important coffee-time discussion just revealed a significant cultural difference between members of staff here in the Department of Theoretical Physics at Maynooth University, which I wish to explore further via a completely scientific poll.

The hyperbolic sine, usually written sinh, is well known to be defined in thuswise fashion:

But the question is how do you pronounce it? Since my schooldays I have always pronounced it like `shine’ whereas I’m told others have pronounced it more like `sinch’. Yet others simply call it hyperbolic sine. What is your pronunciation?

This also gives me the excuse to tell a little story of when I was at school. One morning, which happened to be April 1st, our maths teacher started on the subject of hyperbolic functions, talking about `shine’ and `cosh’ and `tanch’. We all assumed it was an April Fool’s joke and although it was very clever it wasn’t all that funny, particularly as it went on for the whole class. We only realised it wasn’t a joke when he carried on in the same vein the following day…

And another thing, for bonus marks. In all European languages with which I am familiar (which is by no means all), the trigonometric function sin is pronounced `sinus’ not `sine’. Is English the only language to depart from sinus?

### 9 Responses to “Hyperbolic sine, shine or sinsh (or sinch)?”

1. I’ve always said sine h!

2. Though I am inconsistent in that I say cosh, but tan h.

3. shine, cosh and than.
I suspect it’s one of theose things that changes with time?

4. Edd Edmondson Says:

I was taught sinch at school (with the i as per the usual pronunciation of sin, not like cinch), but my partner was taught shine.
Also, our cat is called Sinh, after the tale told here – https://wildcatsmagazine.nl/sacred-cat-of-birma/ but we deliberately mispronounce his name as Shine, after the hyperbolic function.

5. George Jones Says:

My pronunciations are the same as Mark’s,

sine h, cosh, tan h.

6. Bryn Jones Says:

I was taught at school to say “shine”, “cosh” and “tansh”.

7. Phillip Helbig Says:

Sinus hyperbolicus. 🙂

Seriously, I’ve never heard “shine” nor “sinsh”, but have heard the other two.