sqrt, sqrtf, sqrtl - square root function

Syntax	#include <math.h> C11 double sqrt(double x); float sqrtf(float x); long double sqrtf(long double x); (End)
Description	These functions compute the square root of a non-negative floating-point number x.
Return val.	sqrt(x)	if x > = 0.
	0	if x is negative. errno is set to indicate the error.
Errors	sqrt(), sqrtf() and sqrtl() will fail if:
	EDOM	The value of x is negative.
See also	exp(), hypot(), log(), log10(), pow(), sinh(), math.h.