# Function atan Calculate the inverse tangent of a value. For matrices, the function is evaluated element wise. ## Syntax ```js math.atan(x) ``` ### Parameters Parameter | Type | Description --------- | ---- | ----------- `x` | number | BigNumber | Complex | Array | Matrix | Function input ### Returns Type | Description ---- | ----------- number | BigNumber | Complex | Array | Matrix | The arc tangent of x ### Throws Type | Description ---- | ----------- ## Examples ```js math.atan(0.5) // returns number 0.4636476090008061 math.atan(math.tan(1.5)) // returns number 1.5 math.atan(2) // returns Complex 1.5707963267948966 -1.3169578969248166 i ``` ## See also [tan](tan.md), [asin](asin.md), [acos](acos.md)