# sici
> Compute the sine and cosine integrals.
The sine integral is defined as
and the cosine integral is defined as
where `γ` is the [Euler-Mascheroni][eulergamma] constant.
## Usage
```javascript
var sici = require( '@stdlib/math/base/special/sici' );
```
#### sici( \[out,] x )
Computes the sine and cosine integrals.
```javascript
var v = sici( 3.0 );
// returns [ ~1.849, ~0.12 ]
v = sici( 0.0 );
// returns [ 0.0, -Infinity ]
v = sici( -9.0 );
// returns [ ~-1.665, ~0.055 ]
v = sici( NaN );
// returns [ NaN, NaN ]
```
By default, the function returns the sine and cosine integrals as a two-element `array`. To avoid unnecessary memory allocation, the function supports providing an output (destination) object.
```javascript
var Float64Array = require( '@stdlib/array/float64' );
var out = new Float64Array( 2 );
var v = sici( out, 3.0 );
// returns [ ~1.849, ~0.12 ]
var bool = ( v === out );
// returns true
```
## Examples
```javascript
var randu = require( '@stdlib/random/base/randu' );
var sici = require( '@stdlib/math/base/special/sici' );
var x;
var y;
var i;
for ( i = 0; i < 100; i++ ) {
x = randu() * 100.0;
y = sici( x );
console.log( 'si(%d) = %d, ci(%d) = %d', x, y[ 0 ], x, y[ 1 ] );
}
```
[eulergamma]: http://mathworld.wolfram.com/Euler-MascheroniConstant.html
