# R - atan() Function

The R atan() function returns arc tangent of a value. The return value will be in the range -𝜋/2 through 𝜋/2. In special cases it returns the following:

• If the argument is NaN, then the result is NaN.

Note: atan() is the inverse of tan().

### Syntax

```atan(x)
```

### Parameters

 `x` `Required. `Specify column to compute on.

### Return Value

Returns the arc tangent of the value.

### Example:

In the example below, atan() function is used to find out the arc tangent of the value.

```#operating on single element atomic vector
print(atan(-2))
print(atan(0))
print(atan(2))

cat("\nOperating on vector\n")
#operating on vector
v <- c(0, 1, 2)
print(atan(v))

cat("\nOperating on matrix\n")
#operating on matrix
m <- matrix(c(-2, -1, 0, 1, 2, NaN), nrow=2)
print(atan(m))

cat("\nOperating on first column of matrix\n")
#operating on first column of matrix
print(atan(m[,1]))
```

The output of the above code will be:

``` -1.107149
 0
 1.107149

Operating on vector
 0.0000000 0.7853982 1.1071487

Operating on matrix
[,1]      [,2]     [,3]
[1,] -1.1071487 0.0000000 1.107149
[2,] -0.7853982 0.7853982      NaN

Operating on first column of matrix
 -1.1071487 -0.7853982
```

❮ R Math Functions

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