mathjs/docs/reference/functions/unaryMinus.md

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser and offers an integrated solution to work with numbers, big numbers, complex numbers, units, and matrices.

# Function unaryMinus

Inverse the sign of a value, apply a unary minus operation.

For matrices, the function is evaluated element wise. Boolean values and
strings will be converted to a number. For complex numbers, both real and
complex value are inverted.


## Syntax

```js
math.unaryMinus(x)
```

### Parameters

Parameter | Type | Description
--------- | ---- | -----------
`x` | Number | BigNumber | Boolean | String | Complex | Unit | Array | Matrix | null | Number to be inverted.

### Returns

Type | Description
---- | -----------
Number | BigNumber | Complex | Unit | Array | Matrix | Returns the value with inverted sign.


## Examples

```js
math.unaryMinus(3.5);      // returns -3.5
math.unaryMinus(-4.2);     // returns 4.2
```


## See also

[add](add.md),
[subtract](subtract.md),
[unaryPlus](unaryPlus.md)


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