In this article, you will learn about C math library function asin() that returns arc sine value, with explanation and example.

asin() is the standard C math library function that is defined in math library math.h.

#include<math.h>

Function prototype of C math library function asin()

double asin( double x );

where,

x = floating point value between 1 and -1 (1 >= x >= -1).

Return Value of asin()

This function returns the arc sine (inverse sine) in radians of x that ranges in the interval [ -pi / 2, +pi / 2 ].

Note: asin() takes argument between 1 and -1 because the value of sine is in the range of 1 and -1.

Example: Program to demonstrate the use of C math library function asin()

/*Use of math library function asin*/

#include<stdio.h>
#include<math.h>
#define PI 3.1415926

int main()
{
 double x, y;

 x = 0.5;
 y = -0.5;

 //calculation arc sine in radians
 printf("asin(%.2lf) = %.2lf (radians)\n\n", x, asin( x ));

 //calculation arc sine in degrees
 printf("asin(%.2lf) = %.2lf (degree)\n\n", x, asin( x ) * 180 / PI );

 //calculation arc sine in radians
 printf("asin(%.2lf) = %.2lf (radians)\n\n", y, asin( y ));

 //calculation arc sine in degrees
 printf("asin(%.2lf) = %.2lf (degree)\n", y, asin( y ) * 180 / PI );


 return 0;
}

Output

 

Explanation

In the above program, we have calculated the arc sine of x and y in radian and degree.

We have defined macro PI for representing the value of pi.