 # C math library function sin()

In this tutorial, you will learn about C math library function sin() that computes the sine of the argument. `sin()` is the built in standard math library function that is defined in math library `math.h`.

``#include<math.h>``

## Function prototype of C math library function sin()

``double sin( double x );``

where,

x = angle in radians ( floating point value )

### Return Value of sin()

This function returns the sine value of `x.`

The return type is double and ranges between 1 and -1.

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

``````/*Use of math library function cos()*/

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

#define PI 3.1415926

int main()
{
double x ;

x = 45;
//calculation of sine
printf("\nsin( %.3lf ) = %.3lf\n", x, sin( (x * PI) / 180 ));

x = 90;
//calculation of sine
printf("\nsin( %.3lf ) = %.3lf\n", x, sin( (x * PI) / 180 ));

x = 120;
//calculation of sine
printf("\nsin( %.3lf ) = %.3lf\n", x, sin( (x * PI) / 180 ));

return 0;
}
``````

Output Explanation

In the above program, we have calculated the sine of `x`.