sqrt

square root function

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)$=\sqrt x$

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

Example 1

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	•		•
Real sqrt	•	•	•	•
Complex sqrt	•		•		•
Complex csqrt		•			•