### _fcos -- Calculate Cosine

Format

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

Language Level: Extension
_fcos calculates the cosine 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 and return only the cosine.

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

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

Return Value
_fcos returns the cosine expressed in radians.

Example
This example calculates y to be the cosine of x.

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

    int main(void)
    {
       double x;

       x = 7.2;
       printf("The cosine of %lf is %lf.\n", x, _fcos(x));
       return 0;

       /**************************************************
          The output should be similar to:

          The cosine of 7.200000 is 0.608351.
       **************************************************/
    }

cos -- Calculate Cosine
cosh -- Calculate Hyperbolic Cosine
_facos -- Calculate Arccosine
_fcossin -- Calculate Cosine and Sine
_fsincos -- Calculate Sine and Cosine
<builtin.h>