sqrt
From cppreference.com
                    
                                        
                    
                    
                                                            
                    | Defined in header <math.h>
  | ||
| float       sqrtf( float arg ); | (since C99) | |
| double      sqrt( double arg ); | ||
| long double sqrtl( long double arg ); | (since C99) | |
Computes square root of arg.
[edit] Parameters
| arg | - | floating point or integer value | 
[edit] Return value
Square root of arg.
Domain error occurs if arg is negative. NAN is returned in that case.
[edit] See also
| (C99) | computes cubic root  (3√x) (function) | 
| raises a number to the given power (xy) (function) | |