sqrt

Square root function

Contents

Interface
Description
Special Values
Standards
Compatibility
Page Comments

Interface

#include <math.h>double  sqrt (double x)
long  sqrtl (long double x)
float  sqrtf (float x)

#include <complex.h>complex  sqrt (complex x)
double complex  csqrt (double complex x)
float complex  csqrtf (float complex x)
long double complex  csqrtl (long double complex x)

Description

The sqrt function computes the non-negative square root of x, i.e

sqrt(x) $\inline =\sqrt x$

For complex numbers x, sqrt returns the complex root of x, using the following formula

$\sqrt{x} = \sqrt { \mathrm{abs}(x)} \left[ \cos\left(\frac{\mathrm{arg}(x)}{2}\right) + i \sin\left(\frac{\mathrm{arg}(x)}{2}\right) \right]$

(1)

where $\inline \mathrm{arg}(x)$ is the argument of x.

Example:

Example - Square root function

Workings

#include <stdio.h>
#include <math.h>
int main()
{
  double x = 1234321;
  double result = sqrt(x);
  printf("The square root of %.2lf is %.2lf\n", x, result);
  return 0;
}

Solution

Ouput:

The square root of 1234321.00 is 1111.00

Special Values

sqrt ( -0 ) returns -0.

sqrt ( x ) returns a NaN and generates a domain error for x < 0.

Standards

The sqrt function conforms to ISO/IEC 9899:1999(E).

Compatibility

	DOS	UNIX	Windows	ANSI C	C++ only
sqrtl	â€¢		â€¢
Real sqrt	â€¢	â€¢	â€¢	â€¢
Complex sqrt	â€¢		â€¢		â€¢
Complex csqrt		â€¢			â€¢

double	`sqrt` (double x)
long	`sqrtl` (long double x)
float	`sqrtf` (float x)

complex	`sqrt` (complex x)
double complex	`csqrt` (double complex x)
float complex	`csqrtf` (float complex x)
long double complex	`csqrtl` (long double complex x)