# isNegativeZero
> Test if a double-precision floating-point numeric value is negative zero.
## Usage
```javascript
var isNegativeZero = require( '@stdlib/math/base/assert/is-negative-zero' );
```
#### isNegativeZero( x )
Tests if a double-precision floating-point `numeric` value is negative zero.
```javascript
var bool = isNegativeZero( -0.0 );
// returns true
bool = isNegativeZero( 0.0 );
// returns false
```
## Examples
```javascript
var isNegativeZero = require( '@stdlib/math/base/assert/is-negative-zero' );
var bool = isNegativeZero( -0.0 );
// returns true
bool = isNegativeZero( 0.0 );
// returns false
bool = isNegativeZero( 5.0 );
// returns false
bool = isNegativeZero( -1.0 );
// returns false
bool = isNegativeZero( NaN );
// returns false
```