SQRT(3)

NAME
cbrt, cbrtf, sqrt, sqrtf - cube root and square root functions

SYNOPSIS
#include <math.h>
double
cbrt(double x);
float
cbrtf(float x);
double
sqrt(double x);
float
sqrtf(float x);

DESCRIPTION
The cbrt() and the cbrtf() functions compute the cube root of x.

The sqrt() and the sqrtf() functions compute the non-negative square root of x.

RETURN VALUES
The cbrt() and the cbrtf() functions return the requested cube root. The sqrt() and the sqrtf() functions return the requested square root unless an error occurs. On the VAX or Tahoe processor an attempt to take the sqrt() of negative x causes an error; in this event, the global variable errno is set to EDOM and a reserved operand fault is generated.

ERROR (due to Roundoff etc.)
The cbrt() function is accurate to within 0.7 ulps.

The sqrt() function on a VAX is accurate to within 0.501 ulps. Sqrt on a machine that conforms to IEEE 754 is correctly rounded in accordance with the rounding mode in force; the error is less than half an ulp in the default mode (round-to-nearest). An ulp is one Unit in the Last Place carried.

SEE ALSO
math(3), infnan(3)

STANDARDS
The sqrt function conforms to ansiC.

HISTORY
The cbrt function appeared in 4.3BSD.