Standard math library functions

Commonly used standard math library functions

All functions return a double result and assume arguments are double x,y;
Include '#include ' at the top of the source file and link with '-lm' on the gcc command line.
On Linux type 'man function' to get a manual page on a given function.

sin of x with x in radians	`sin(x)`
cosine of x with x in radians	`cos(x)`
tangent of x with x in radians	`tan(x)`
arctangent of x, returning 2 quadrant value in radians	`atan(x)`
arctangent of y/x, returning 4 quadrant value in radians	`atan2(y,x)`
e to the power x	`exp(x)`
natural log of x	`log(x)`
base 10 log of x	`log10(x)`
hyperbolic sin of x	`sinh(x)`
hyperbolic cosine of x	`cosh(x)`
square root of x	`sqrt(x)`
x to the power y	`pow(x,y)`
absolute value of x	`fabs(x)`