---
title: math.exp2() function
description: >
  `math.exp2()` returns `2**x`, the base-2 exponential of `x`.
menu:
  flux_v0_ref:
    name: math.exp2
    parent: math
    identifier: math/exp2
weight: 101
---

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`math.exp2()` returns `2**x`, the base-2 exponential of `x`.



##### Function type signature

```js
(x: float) => float
```

{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}

## Parameters

### x
({{< req >}})
Value to operate on.




## Examples

- [Return the base-2 exponential of a value](#return-the-base-2-exponential-of-a-value)
- [Use math.exp2 in map](#use-mathexp2-in-map)

### Return the base-2 exponential of a value

```js
import "math"

math.exp2(x: 21.0)// 2.097152e+06


```


### Use math.exp2 in map

```js
import "sampledata"
import "math"

sampledata.float()
    |> map(fn: (r) => ({r with _value: math.exp2(x: r._value)}))

```

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{{% expand "View example input and output" %}}

#### Input data

| _time                | *tag | _value  |
| -------------------- | ---- | ------- |
| 2021-01-01T00:00:00Z | t1   | -2.18   |
| 2021-01-01T00:00:10Z | t1   | 10.92   |
| 2021-01-01T00:00:20Z | t1   | 7.35    |
| 2021-01-01T00:00:30Z | t1   | 17.53   |
| 2021-01-01T00:00:40Z | t1   | 15.23   |
| 2021-01-01T00:00:50Z | t1   | 4.43    |

| _time                | *tag | _value  |
| -------------------- | ---- | ------- |
| 2021-01-01T00:00:00Z | t2   | 19.85   |
| 2021-01-01T00:00:10Z | t2   | 4.97    |
| 2021-01-01T00:00:20Z | t2   | -3.75   |
| 2021-01-01T00:00:30Z | t2   | 19.77   |
| 2021-01-01T00:00:40Z | t2   | 13.86   |
| 2021-01-01T00:00:50Z | t2   | 1.86    |


#### Output data

| _time                | _value              | *tag |
| -------------------- | ------------------- | ---- |
| 2021-01-01T00:00:00Z | 0.22067574907266369 | t1   |
| 2021-01-01T00:00:10Z | 1937.5260604940204  | t1   |
| 2021-01-01T00:00:20Z | 163.1437602968655   | t1   |
| 2021-01-01T00:00:30Z | 189258.68751552477  | t1   |
| 2021-01-01T00:00:40Z | 38431.45561643022   | t1   |
| 2021-01-01T00:00:50Z | 21.55573722985104   | t1   |

| _time                | _value              | *tag |
| -------------------- | ------------------- | ---- |
| 2021-01-01T00:00:00Z | 945029.6050826148   | t2   |
| 2021-01-01T00:00:10Z | 31.341449522781655  | t2   |
| 2021-01-01T00:00:20Z | 0.07432544468767006 | t2   |
| 2021-01-01T00:00:30Z | 894052.4842704767   | t2   |
| 2021-01-01T00:00:40Z | 14868.793840716358  | t2   |
| 2021-01-01T00:00:50Z | 3.6300766212686435  | t2   |

{{% /expand %}}
{{< /expand-wrapper >}}