Trig functions across various programming languages

Unfortunately programming languages are inconsistent in how the support trig functions and their inverses. The table below summarizes how to call trig functions in several languages. Note that "C" means the C language itself but also a large number of other programming languages, like Python and JavaScript, that follow C's conventions.

Mathematica	bc	C	NumPy	Perl	Math::Trig	CL
Sin	s	sin	sin	sin	-	sin
Cos	c	cos	cos	cos	-	cos
Tan	-	tan	tan	-	tan	tan
Sec	-	-	-	-	sec	-
Csc	-	-	-	-	csc	-
Cot	-	-	-	-	cot	-
ArcSin	-	asin	arcsin	-	asin	asin
ArcCos	-	acos	arccos	-	acos	acos
ArcTan 1 arg	a	atan	arctan	-	atan	atan
ArcTan 2 arg	-	atan2	arctan2	atan2	atan2	atan
ArcSec	-	-	-	-	asec	-
ArcCsc	-	-	-	-	acsc	-
ArcCot	-	-	-	-	acot	-

This blog post goes through the table in detail. For example, it explains why Mathematica's ArcTan with two arguments doesn't always return the same value as C's atan2.