# ee.Number.acos

Computes the arccosine in radians of the input.

<br />

| Usage | Returns |
|---|---|
| `Number.acos()` | Number |

| Argument | Type | Details |
|---|---|---|
| this: `input` | Number | The input value. |

## Examples

### Code Editor (JavaScript)

```javascript
// The domain of arccosine is [-1,1], inputs outside the domain are invalid.
print('Arccosine of -1', ee.Number(-1).acos());  // 3.141592653 (π)
print('Arccosine of 0', ee.Number(0).acos());  // 1.570796326 (π/2)
print('Arccosine of 1', ee.Number(1).acos());  // 0
```
Python setup

See the [Python Environment](https://developers.google.com/earth-engine/guides/python_install) page for information on the Python API and using
`geemap` for interactive development.

```python
import ee
import geemap.core as geemap
```

### Colab (Python)

```python
# The domain of arccosine is [-1,1], inputs outside the domain are invalid.
display('Arccosine of -1:', ee.Number(-1).acos())  # 3.141592653 (π)
display('Arccosine of 0:', ee.Number(0).acos())  # 1.570796326 (π/2)
display('Arccosine of 1:', ee.Number(1).acos())  # 0
```