time-to-botec/js/node_modules/@stdlib/math/base/special/besselj0/README.md

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# j0
> Compute the [Bessel function of the first kind][bessel-first-kind] of order zero.
<section class="intro">
The [Bessel function of the first kind][bessel-first-kind] of order zero is defined as
<!-- <equation class="equation" label="eq:bessel_first_kind_order_zero" align="center" raw="J_0 (x) = \frac{1}{2 \pi} \int_{-\pi}^\pi e^{- i x \sin(\tau)} \,d\tau." alt="Bessel function of the first kind of order zero"> -->
<div class="equation" align="center" data-raw-text="J_0 (x) = \frac{1}{2 \pi} \int_{-\pi}^\pi e^{- i x \sin(\tau)} \,d\tau." data-equation="eq:bessel_first_kind_order_zero">
<img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@bb29798906e119fcb2af99e94b60407a270c9b32/lib/node_modules/@stdlib/math/base/special/besselj0/docs/img/equation_bessel_first_kind_order_zero.svg" alt="Bessel function of the first kind of order zero">
<br>
</div>
<!-- </equation> -->
</section>
<!-- /.intro -->
<section class="usage">
## Usage
```javascript
var j0 = require( '@stdlib/math/base/special/besselj0' );
```
#### j0( x )
Compute the [Bessel function of the first kind][bessel-first-kind] of order zero at `x`.
```javascript
var v = j0( 0.0 );
// returns 1.0
v = j0( 1.0 );
// returns ~0.765
v = j0( Infinity );
// returns 0.0
v = j0( -Infinity );
// returns 0.0
v = j0( NaN );
// returns NaN
```
</section>
<!-- /.usage -->
<section class="examples">
## Examples
<!-- eslint no-undef: "error" -->
```javascript
var randu = require( '@stdlib/random/base/randu' );
var j0 = require( '@stdlib/math/base/special/besselj0' );
var x;
var i;
for ( i = 0; i < 100; i++ ) {
x = randu() * 10.0;
console.log( 'j0(%d) = %d', x, j0( x ) );
}
```
</section>
<!-- /.examples -->
<section class="links">
[bessel-first-kind]: https://en.wikipedia.org/wiki/Bessel_function#Bessel_functions_of_the_first_kind:_J.CE.B1
</section>
<!-- /.links -->