# ee.Array.atan

On an element-wise basis, computes the arctangent in radians of the input.

<br />

| Usage | Returns |
|---|---|
| `Array.atan()` | Array |

| Argument | Type | Details |
|---|---|---|
| this: `input` | Array | The input array. |

## Examples

### Code Editor (JavaScript)

```javascript
print(ee.Array([-5]).atan());  // [-1.3734]
print(ee.Array([0]).atan());  // [0]
print(ee.Array([5]).atan());  // [1.3734]

var start = -5;
var end = 5;
var points = ee.Array(ee.List.sequence(start, end, null, 50));
var values = points.atan();

// Plot atan() defined above.
var chart = ui.Chart.array.values(values, 0, points)
    .setOptions({
      viewWindow: {min: start, max: end},
      hAxis: {
        title: 'x',
        viewWindowMode: 'maximized',
        ticks: [
          {v: start, f: start},
          {v: 0, f: 0},
          {v: end, f: end}]
      },
      vAxis: {
        title: 'atan(x)',
        ticks: [
          {v: -Math.PI / 2, f: '-π/2'},
          {v: 0, f: 0},
          {v: Math.PI / 2, f: 'π/2'}]
      },
      lineWidth: 1,
      pointSize: 0,
    });
print(chart);
```
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
import math
import altair as alt
import pandas as pd

display(ee.Array([-5]).atan())  # [-1.3734]
display(ee.Array([0]).atan())  # [0]
display(ee.Array([5]).atan())  # [1.3734]

start = -5
end = 5
points = ee.Array(ee.List.sequence(start, end, None, 50))
values = points.atan()

df = pd.DataFrame({'x': points.getInfo(), 'atan(x)': values.getInfo()})

# Plot atan() defined above.
alt.Chart(df).mark_line().encode(
    x=alt.X('x', axis=alt.Axis(values=[start, 0, end])),
    y=alt.Y('atan(x)', axis=alt.Axis(values=[-math.pi / 2, 0, math.pi / 2]))
)
```