# sqrt1pm1
> Compute `sqrt( 1 + x ) - 1`.
## Usage
```javascript
var sqrt1pm1 = require( '@stdlib/math/base/special/sqrt1pm1' );
```
#### sqrt1pm1( x )
Computes `sqrt( 1 + x ) - 1` more accurately for small `x`.
```javascript
var v = sqrt1pm1( 3.0 );
// returns 1.0
v = sqrt1pm1( 0.5 );
// returns ~0.225
v = sqrt1pm1( 0.02 );
// returns ~0.01
v = sqrt1pm1( -0.5 );
// returns ~-0.293
v = sqrt1pm1( -1.1 );
// returns NaN
v = sqrt1pm1( NaN );
// returns NaN
```
## Examples
```javascript
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var sqrt1pm1 = require( '@stdlib/math/base/special/sqrt1pm1' );
var x;
var i;
for ( i = 0; i < 100; i++ ) {
x = round( randu() * 100.0 );
console.log( 'sqrt(1+%d) - 1 = %d', x, sqrt1pm1( x ) );
}
```