# ATAN2

`atan2( dx, dy )`

atan2 | "2-argument arctangent" |

dx | a number |

dy | a number |

The **atan2( )** function is used to return the angle of the numbers provided.

An example from the manual shows us how to get and draw the angle between two points using `atan2`

:

```
X=20 Y=30
FUNCTION _UPDATE()
IF (BTN(0)) X-=2
IF (BTN(1)) X+=2
IF (BTN(2)) Y-=2
IF (BTN(3)) Y+=2
END
FUNCTION _DRAW()
CLS()
CIRCFILL(X,Y,2,14)
CIRCFILL(64,64,2,7)
A=ATAN2(X-64, Y-64)
PRINT("ANGLE: "..A)
LINE(64,64,
64+COS(A)*10,
64+SIN(A)*10,7)
END
```

We've added some more details to show what is happening here:

`angle = atan2( x1-x2, y1-y2 )`

Using the `angle`

found with `atan2()`

and combining it with `cos(angle)`

and `sin(angle)`

, we are able to draw the line that always points from one point to the other.

267

4 Sep 2023