Format
#include <builtin.h> double _facos(double x);
Language Level: Extension
_facos calculates the arccosine of x.
This function causes the compiler to emit the appropriate 80387
instructions for the calculation of the arccosine.
Because it is a built-in function and has no backing code in the library:
Return Value
_facos returns the arccosine of x.
Example
This example prompts for a value for x.
It prints an error message if x is greater than 1 or
less than -1. Otherwise, it assigns the arccosine of x
to y.
#include <builtin.h> #include <stdio.h>
#define MAX 1.0 #define MIN -1.0
int main(void)
{
double x;
printf("Enter x:\n");
scanf("%lf", &x);
/* Output error if not in range */
if (MAX < x)
printf("Error: %lf too small for acos.\n", x);
else
printf("The arccosine of %lf is %lf.\n", x, _facos(x));
return 0;
/**************************************************************
Assuming you enter: -1.0
The output should be:
The arccossine of -1.000000 is 3.141593. **************************************************************/ }
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acos -- Calculate Arccosine
cos -- Calculate
Cosine
cosh -- Calculate
Hyperbolic Cosine
_fcos -- Calculate
Cosine
_fcossin --
Calculate Cosine and Sine
_fsincos --
Calculate Sine and Cosine
<builtin.h>