SQRT(3) BSD Programmer's Manual SQRT(3)
NAME
cbrt, sqrt  cube root and square root functions
SYNOPSIS
#include <<math.h>>
double
cbrt(double x);
double
sqrt(double x);
DESCRIPTION
The cbrt() function computes the cube root of x.
The sqrt() computes the nonnegative square root of x.
RETURN VALUES
The cbrt() function returns the requested cube root. The sqrt() function
returns 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 er
ror; in this event, the global variable errno is set to EDOM and a re
served 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 de
fault mode (roundtonearest). An ulp is one Unit in the Last Place car
ried.
SEE ALSO
math(3), infnan(3)
STANDARDS
The sqrt function conforms to ANSI C X3.1591989 (``ANSI C '').
HISTORY
The cbrt function appeared in 4.3BSD.
4.4BSD June 4, 1993 1
