time-to-botec/js/node_modules/@stdlib/math/base/special/bessely0/README.md

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# y0
> Compute the [Bessel function of the second kind][bessel-second-kind] of order zero.
<section class="intro">
The [Bessel function of the second kind][bessel-second-kind] of order zero is defined as
<!-- <equation class="equation" label="eq:bessel_second_kind_order_zero" align="center" raw="Y_0(x) = \frac{1}{\pi} \int_0^\pi \sin(x \sin\theta) \, d\theta -\frac{2}{\pi} \int_0^\infty e^{-x \sinh t} \, dt." alt="Bessel function of the second kind of order zero"> -->
<div class="equation" align="center" data-raw-text="Y_0(x) = \frac{1}{\pi} \int_0^\pi \sin(x \sin\theta) \, d\theta -\frac{2}{\pi} \int_0^\infty e^{-x \sinh t} \, dt." data-equation="eq:bessel_second_kind_order_zero">
<img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@bb29798906e119fcb2af99e94b60407a270c9b32/lib/node_modules/@stdlib/math/base/special/bessely0/docs/img/equation_bessel_second_kind_order_zero.svg" alt="Bessel function of the second kind of order zero">
<br>
</div>
<!-- </equation> -->
</section>
<!-- /.intro -->
<section class="usage">
## Usage
```javascript
var y0 = require( '@stdlib/math/base/special/bessely0' );
```
#### y0( x )
Computes the [Bessel function of the second kind][bessel-second-kind] of order zero at `x`.
```javascript
var v = y0( 0.0 );
// returns -Infinity
v = y0( 1.0 );
// returns ~0.088
v = y0( Infinity );
// returns 0.0
```
If `x < 0` or `x` is `NaN`, the function returns `NaN`.
```javascript
var v = y0( -1.0 );
// returns NaN
v = y0( -Infinity );
// returns NaN
v = y0( NaN );
// returns NaN
```
</section>
<!-- /.usage -->
<section class="examples">
## Examples
<!-- eslint no-undef: "error" -->
```javascript
var randu = require( '@stdlib/random/base/randu' );
var y0 = require( '@stdlib/math/base/special/bessely0' );
var x;
var i;
for ( i = 0; i < 100; i++ ) {
x = randu() * 10.0;
console.log( 'y0(%d) = %d', x, y0( x ) );
}
```
</section>
<!-- /.examples -->
<section class="links">
[bessel-second-kind]: https://en.wikipedia.org/wiki/Bessel_function#Bessel_functions_of_the_second_kind:_Y.CE.B1
</section>
<!-- /.links -->