README.md

Cosine

Compute the cosine of a number.

Usage

var cos = require( '@stdlib/math/base/special/cos' );

cos( x )

Computes the cosine of a number (in radians).

var v = cos( 0.0 );
// returns 1.0

v = cos( 3.141592653589793/4.0 );
// returns ~0.707

v = cos( -3.141592653589793/6.0 );
// returns ~0.866

v = cos( NaN );
// returns NaN

Examples

var uniform = require( '@stdlib/random/array/uniform' );
var logEachMap = require( '@stdlib/console/log-each-map' );
var TWO_PI = require( '@stdlib/constants/float64/two-pi' );
var cos = require( '@stdlib/math/base/special/cos' );

var opts = {
    'dtype': 'float64'
};
var x = uniform( 100, 0.0, TWO_PI, opts );

logEachMap( 'cos(%0.4f) = %0.4f', x, cos );

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C APIs

Usage

#include "stdlib/math/base/special/cos.h"

stdlib_base_cos( x )

Computes the cosine of a number (in radians).

double out = stdlib_base_cos( 0.0 );
// returns 1.0

out = stdlib_base_cos( 3.141592653589793 / 4.0 );
// returns ~-0.707

The function accepts the following arguments:

• x: [in] double input value.

double stdlib_base_cos( const double x );

Examples

#include "stdlib/math/base/special/cos.h"
#include <stdio.h>

int main( void ) {
    const double x[] = { 0.0, 0.523, 0.785, 1.047, 3.14 };

    double y;
    int i;
    for ( i = 0; i < 5; i++ ) {
        y = stdlib_base_cos( x[ i ] );
        printf( "cos(%lf) = %lf\n", x[ i ], y );
    }
}

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See Also

• @stdlib/math/base/special/cospi: compute cos(πx).
• @stdlib/math/base/special/cosm1: compute the cosine of a number minus one.
• @stdlib/math/base/special/sin: compute the sine of a number.
• @stdlib/math/base/special/tan: evaluate the tangent of a number.