cos(), cosf(), cosl()

Compute the cosine of an angle

Synopsis:

#include <math.h>

double cos( double x );

float cosf( float x );

long double cosl( long double x );

Arguments:

x

The angle, in radians, for which you want to compute the cosine.

Library:

libm

Use the -l m option to qcc to link against this library.

Description:

These functions compute the cosine of x (specified in radians).

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An argument with a large magnitude may yield results with little or no significance.

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Returns:

The cosine of x. When x is +/-Inf, these functions return NaN.

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If an error occurs, these functions return 0, but this is also a valid mathematical result. If you want to check for errors, set errno to 0, call the function, and then check errno again. These functions don't change errno if no errors occurred.

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Examples:

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

int main( void )
{
    double value;

    value = cos( M_PI );
    printf( "value = %f\n", value );
    
    return EXIT_SUCCESS;
}

produces the output:

value = -1.000000

Classification:

ANSI, POSIX 1003.1

See also:

acos(), errno, sin(), tan()