mathjs/docs/reference/functions/tan.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 tan

Calculate the tangent of a value. `tan(x)` is equal to `sin(x) / cos(x)`.

For matrices, the function is evaluated element wise.


## Syntax

```js
math.tan(x)
```

### Parameters

Parameter | Type | Description
--------- | ---- | -----------
`x` | Number | Boolean | Complex | Unit | Array | Matrix | null | Function input

### Returns

Type | Description
---- | -----------
Number | Complex | Array | Matrix | Tangent of x


## Examples

```js
math.tan(0.5);                    // returns Number 0.5463024898437905
math.sin(0.5) / math.cos(0.5);    // returns Number 0.5463024898437905
math.tan(math.pi / 4);            // returns Number 1
math.tan(math.unit(45, 'deg'));   // returns Number 1
```


## See also

[atan](atan.md),
[sin](sin.md),
[cos](cos.md)


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