--- title: "asin" description: "Returns the arc sine of number" --- # asin > Returns the arc sine of number This function is used by Ignition's Expression language. ## Description Returns the arc sine of number, which must be a number between -1 and 1. The results will be an angle expressed in radians in the range of -pi/2 through pi/2. ## Syntax `asin(number)` - Parameters - float **number** - The number to get the arc sine of. Must be between -1 and 1. - Results - float - The arc sine of the number provided. ## Examples ```python title="Code Snippet" asin(.38) //returns 0.3898 ```