README.md

Arccovercosine

Compute the inverse coversed cosine.

The inverse coversed cosine is defined as

$$\mathop{\mathrm{acovercos}}(\theta) = \arcsin(1+\theta)$$

Usage

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

acovercos( x )

Computes the inverse coversed cosine.

var v = acovercos( 0.0 );
// returns ~1.5708

v = acovercos( -3.141592653589793/2.0 );
// returns ~-0.6075

v = acovercos( -3.141592653589793/6.0 );
// returns ~0.4966

If x < -2, x > 0, or x is NaN, the function returns NaN.

var v = acovercos( 1.0 );
// returns NaN

v = acovercos( -3.14 );
// returns NaN

v = acovercos( NaN );
// returns NaN

Examples

var uniform = require( '@stdlib/random/array/uniform' );
var logEachMap = require( '@stdlib/console/log-each-map' );
var acovercos = require( '@stdlib/math/base/special/acovercos' );

var x = uniform( 100, -2.0, 0.0, {
    'dtype': 'float64'
});

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

---

C APIs

Usage

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

stdlib_base_acovercos( x )

Computes the inverse coversed cosine of a double-precision floating-point number.

double out = stdlib_base_acovercos( -3.141592653589793/2.0 );
// returns ~-0.6075

The function accepts the following arguments:

• x: [in] double input value.

double stdlib_base_acovercos( const double x );

Examples

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

int main( void ) {
    const double x[] = { -2.0, -1.80, -1.78, -1.67, -0.56, -0.27, -1.67, -0.78, -1.89, 0.0 };

    double v;
    int i;
    for ( i = 0; i < 10; i++ ) {
        v = stdlib_base_acovercos( x[ i ] );
        printf( "acovercos(%lf) = %lf\n", x[ i ], v );
    }
}

---

See Also

• @stdlib/math/base/special/acoversin: compute the inverse coversed sine.
• @stdlib/math/base/special/avercos: compute the inverse versed cosine.
• @stdlib/math/base/special/covercos: compute the coversed cosine.
• @stdlib/math/base/special/vercos: compute the versed cosine.