Calculates the trigonometric cosine function of a double precision floating-point value.
Include
<math.h>
Prototype
double cos (double x);
Argument
x
Return Value
Returns the cosine of x
in radians in the ranges of -1 to 1
inclusive.
Remarks
A domain error will occur if x
is a NaN or infinity.
Example
#include <math.h>
#include <stdio.h>
#include <errno.h>
int main(void)
{
double x,y;
errno = 0;
x = -1.0;
y = cos (x);
if (errno)
perror("Error");
printf("The cosine of %f is %f\n", x, y);
errno = 0;
x = 0.0;
y = cos (x);
if (errno)
perror("Error");
printf("The cosine of %f is %f\n", x, y);
}
Example Output
The cosine of -1.000000 is 0.540302
The cosine of 0.000000 is 1.000000