NAME

Math: cbrt, sqrt, pow, pow10, hypot, exp, expm1, log, log10, log1p, cos, cosh, sin, sinh, tan, tanh, acos, asin, acosh, asinh, atan, atanh, atan2, lgamma, erf, erfc, j0, j1, y0, y1, jn, yn − elementary functions of applied mathematics

SYNOPSIS

include "math.m";
math := load Math Math->PATH;
 cbrt, sqrt: fn(x: real): real;
pow: fn(x, y: real): real;
pow10: fn(p: int): real;
hypot: fn(x, y: real): real;
exp, expm1, log, log10, log1p: fn(x: real): real;
 cos, cosh, sin, sinh, tan, tanh: fn(x: real): real;
acos, asin, acosh, asinh, atan, atanh: fn(x: real): real;
atan2: fn(y, x: real) of real;
 lgamma: fn(x: real): (int,real);
erf, erfc: fn(x: real): real;
j0, j1, y0, y1: fn(x: real): real;
jn, yn: fn(n: int, x: real): real;
 

DESCRIPTION

These routines implement the basic elementary functions of applied mathematics. 

Sqrt(x) computes the square root of x, cbrt(x) the cube root.  Pow(x,y) computes ­x raised to the exponent y; ­pow10 raises 10 to the integer power n. Hypot(x,y) computes sqrt(x∗x+y∗y). 

Exp(x) returns the exponential function of x, and expm1(x) is exp(x)-1.

Log(x) returns the natural logarithm of x, while log10(x) returns the logarithm base 10 and log1p(x) returns the logarithm of 1+x. 

The trigonometric functions use radians.  The ranges of the inverse functions are: acos in [0,π]; ­asin in [-π/2,π/2]; ­atan in [-π/2,π/2]; and atan2(y,x) ­= arctan(y/x) in [-π,π];

The gamma function is implemented by lgamma(x); the tuple it returns, say (s,lg), encodes the gamma function by Γ(x) = s∗exp(lg). 

The hyperbolic trigonometric functions ­sinh etc. behave as expected.  ­Erf is the error function and erfc(x) is 1-erf(x). 

The Bessel functions are computed by j0, j1, jn, y0, y1, and yn. 

SOURCE

­/interp/math.c

SEE ALSO

math-intro(2)

Plan 9  —  June 29, 2000