# Best way to denote some trigonometric functions

What is the best way to denote tangent and other trigonometric functions: tg or tan, ctg or cot. What notation is commonly used and standardized?

-
FWIW: I'd not say $\tan$ and $\cot$ are "best", but they are the notation that more people understand than $\mathrm{tg}$ and $\mathrm{ctg}$. So, if you're writing for a wide audience, you might consider using the more popular ones. – J. M. Aug 7 '12 at 11:57

In current US textbooks, $\tan$ and $\cot$ are commonly used and standardized. Also: $\sin, \cos, \sec, \csc$. In other countries, and in the 19th century, you will find others.