Vercosine

Compute the versed cosine.

The versed cosine is defined as

$$\mathop{\mathrm{vercos}}(\theta) = 1 + \cos \theta$$

Usage

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

vercos( x )

Computes the versed cosine of a number (in radians).

var v = vercos( 0.0 );
// returns 2.0

v = vercos( 3.141592653589793/2.0 );
// returns 1.0

v = vercos( -3.141592653589793/6.0 );
// returns ~1.8660

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

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

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

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C APIs

Usage

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

stdlib_base_vercos( x )

Computes the versed cosine of a number (in radians).

double out = stdlib_base_vercos( 0.0 );
// returns 2.0

out = stdlib_base_vercos( 3.141592653589793 / 2.0 );
// returns 1.0

The function accepts the following arguments:

• x: [in] double input value.

double stdlib_base_vercos( const double x );

Examples

#include "stdlib/math/base/special/vercos.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_vercos( x[ i ] );
        printf( "vercos(%lf) = %lf\n", x[ i ], y );
    }
}

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See Also

• @stdlib/math/base/special/cos: compute the cosine of a number.
• @stdlib/math/base/special/versin: compute the versed sine.