acosh

Compute the hyperbolic arccosine of a number.

Usage

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

acosh( x )

Computes the hyperbolic arccosine of a number (in radians).

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

v = acosh( 2.0 );
// returns ~1.317

v = acosh( 0.5 );
// returns NaN

The domain of x is restricted to [1,+infinity). If x < 1, the function will return NaN.

var v = acosh( 0.0 );
// returns NaN

Notes

For large x, the function will overflow.

var v = acosh( 1.0e308 );
// returns Infinity
// (expected 709.889355822726)

Examples

var linspace = require( '@stdlib/array/base/linspace' );
var acosh = require( '@stdlib/math/base/special/fast/acosh' );

var x = linspace( 1.0, 5.0, 103 );

var i;
for ( i = 0; i < x.length; i++ ) {
    console.log( acosh( x[ i ] ) );
}

C APIs

Usage

#include "stdlib/math/base/special/fast/acosh.h"

stdlib_base_fast_acosh( x )

Computes the hyperbolic arccosine of a double-precision floating-point number.

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

out = stdlib_base_fast_acosh( 2.0 );
// returns ~1.317

The function accepts the following arguments:

x: [in] double input value.

double stdlib_base_fast_acosh( const double x );

Examples

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

int main( void ) {
    const double x[] = { 1.0, 1.45, 1.89, 2.33, 2.78, 3.22, 3.66, 4.11, 4.55, 5.0 };
    
    double v;
    int i;
    for ( i = 0; i < 10; i++ ) {
        v = stdlib_base_fast_acosh( x[ i ] );
        printf( "acosh(%lf) = %lf\n", x[ i ], v );
    }
}