# Ruby | Math atan() function

The atan() is an inbuilt function in Ruby returns the arc tangent of a number means give a tangent value to this function it will return the angle in radian corresponding to that value. arc tangent is the inverse operation of tangent. This function accepts all numbers in range [-inf, +inf].

Syntax: Math.atan(value)

Parameters: The function accepts one mandatory parameter value whose corresponding angle we have to find.

Return Value: It returns the angle in radians which in range -pi/2 to +pi/2.

Example 1:

 `#Ruby program for atan() function ` ` `  `#Assigning values ` `val1 = 1 val2 = 0.5 val3 = -1 val4 = -0.9 ` ` `  `#Prints the atan() value ` `                                      ``puts` `Math.``atan``(val1) ` `                                          ``puts` `Math.``atan``(val2) ` `                                              ``puts` `Math.``atan``(val3) ` `                                                  ``puts` `Math.``atan``(val4) `

Output:

```0.7853981633974483
0.4636476090008061
-0.7853981633974483
-0.7328151017865066
```

Example 2:

 `#Ruby program for atan() function ` ` `  `#Assigning values ` `val1 = 0.9 val2 = 0.2 val3 = -0.78 val4 = -0.32 ` ` `  `#Prints the atan() value ` `                                           ``puts` `Math.``atan``(val1) ` `                                               ``puts` `Math.``atan``(val2) ` `                                                   ``puts` `Math.``atan``(val3) ` `                                                       ``puts` `Math.``atan``(val4) `

Output:

```0.7328151017865066
0.19739555984988078
-0.6624262938331512
-0.3097029445424562
```

My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Article Tags :

Be the First to upvote.

Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.