|
<cmath>
double asin ( double x );
float asin ( float x );
long double asin ( long double x );
Compute arc sine
Returns the principal value of the arc sine of x, expressed in radians.
In trigonometrics, arc sine is the inverse operation of sine.
In C++, this function is overloaded in <valarray> (see valarray asin).
Parameters
- x
- Floating point value in the interval [-1,+1].
If the argument is out of this interval, a domain error occurs, setting the global variable errno to the value EDOM.
Return Value
Arc sine of x, in the interval [-pi/2,+pi/2] radians.
Portability
In C, only the double version of this function exists with this name.
Example
1
2
3
4
5
6
7
8
9
10
11
12
13
14
|
/* asin example */
#include <stdio.h>
#include <math.h>
#define PI 3.14159265
int main ()
{
double param, result;
param = 0.5;
result = asin (param) * 180.0 / PI;
printf ("The arc sine of %lf is %lf degrees\n", param, result );
return 0;
}
|
Output:
The arc sine of 0.500000 is 30.000000 degrees.
|
See also
| sin | Compute sine (function) |
| acos | Compute arc cosine (function) |
|