### _fsin -- Calculate Sine

Format

>     #include <builtin.h>
>     double _fsin( double x);

Language Level: Extension
_fsin calculates the sine of x, where x is expressed in radians. The value of x must be less than 2**63. This function causes the compiler to emit the appropriate 80387 instruction for the calculation of sine.

Because it is a built-in function and has no backing code in the library:

- You cannot take the address of _fsin.
- You cannot parenthesize a _fsin function call, because parentheses specify a call to the backing code for the function in the library.

Return Value
This function returns the sine of a variable x expressed in radians.

Example
This example calculates y as the sine of pi/2.

    #include <builtin.h>
    #include <stdio.h>

    int main(void)
    {
       double PI;

       pi = 3.1415926535;
       printf("The sine of %lf is %lf.\n", pi/2.0, _fsin(pi/2.0));
       return 0;

       /**********************************************************
          The output should be:

          The sine of 1.570796 is 1.000000.
       **********************************************************/
    }

_fasin -- Calculate Arcsine
_fcossin -- Calculate Cosine and Sine
_fsincos -- Calculate Sine and Cosine
sin -- Calculate Sine
sinh -- Calculate Hyperbolic Sine
<builtin.h>