asin Function

Calculates the trigonometric arc sine function of a double precision floating-point value.

Include

<math.h>

Prototype

double asin (double x);

Argument

x

value between -1 and 1 for which to return the arc sine

Return Value

Returns the arc sine in radians in the range of -pi/2 to +pi/2 (inclusive).

Remarks

A domain error occurs if x is less than -1 or greater than 1.

Example

#include <math.h>
#include <stdio.h>
#include <errno.h>

int main(void)
{
  double x, y;

  errno = 0;
  x = 2.0;
  y = asin (x);
  if (errno)
    perror("Error");
  printf("The arcsine of %f is %f\n", x, y);

  errno = 0;
  x = 0.0;
  y = asin (x);
  if (errno)
    perror("Error");
  printf("The arcsine of %f is %f\n", x, y);
}

Example Output

Error: domain error
The arcsine of 2.000000 is nan
The arcsine of 0.000000 is 0.000000