# Capitalising trigonometric functions

1. Dec 10, 2012

### EricPowell

I have always capitalised the first letter of my trigonometric functions, for example, writing Sinθ as opposed to the usual sinθ. Is it wrong to capitalise them? Does it make a difference in meaning?

2. Dec 10, 2012

### Vorde

It does not, however that is not common practice.

3. Dec 11, 2012

### Curious3141

It might make a difference, depending on your convention. Restricted sine and cosine functions sometimes have the first letter capitalised. Read: http://www.cliffsnotes.com/study_guide/Inverse-Cosine-and-Inverse-Sine.topicArticleId-11658,articleId-11639.html [Broken]

Last edited by a moderator: May 6, 2017
4. Dec 14, 2012

### Boorglar

I think I've heard that Sin(x) was used for a different definition of the sine function, like sin(some constant* x).

EDIT: after looking up on the internet, I haven't found anything supporting my claim yet, so I could be wrong.

Last edited: Dec 14, 2012
5. Dec 14, 2012

### Staff: Mentor

In some texts, Sin(x) is the sine function restricted to its principal domain, [-$\pi/2, \pi/2$].

Similarly, Cos(x) is the cosine function restricted to its principal domain, [0, $\pi$].

6. Dec 14, 2012

### Michael Redei

I've seen both Sin and Cos refer to the complex extensions of sin and cos. So it seems as if different authors use the capitalised forms for different variants.