# Function asec Calculate the inverse secant of a value. Defined as `asec(x) = acos(1/x)`. For matrices, the function is evaluated element wise. ## Syntax ```js math.asec(x) ``` ### Parameters Parameter | Type | Description --------- | ---- | ----------- `x` | number | Complex | Array | Matrix | Function input ### Returns Type | Description ---- | ----------- number | Complex | Array | Matrix | The arc secant of x ### Throws Type | Description ---- | ----------- ## Examples ```js math.asec(0.5) // returns 1.0471975511965979 math.asec(math.sec(1.5)) // returns 1.5 math.asec(2) // returns 0 + 1.3169578969248166 i ``` ## See also [acos](acos.md), [acot](acot.md), [acsc](acsc.md)