mozilla
Your Search Results

    Math.asin()

    Summary

    The Math.asin() function returns the arcsine (in radians) of a number, that is

    x[-1;1],Math.asin(x)=arcsin(x)= the unique y[-π2;π2]such thatsin(y)=x\forall x \in [{-1};1],\;\mathtt{\operatorname{Math.asin}(x)} = \arcsin(x) = \text{ the unique } \; y \in \left[-\frac{\pi}{2}; \frac{\pi}{2}\right] \, \text{such that} \; \sin(y) = x

    Syntax

    Math.asin(x)

    Parameters

    x
    A number.

    Description

    The Math.asin() method returns a numeric value between -π2-\frac{\pi}{2} and π2\frac{\pi}{2} radians for x between -1 and 1. If the value of x is outside this range, it returns NaN.

    Because asin() is a static method of Math, you always use it as Math.asin(), rather than as a method of a Math object you created (Math is not a constructor).

    Examples

    Example: Using Math.asin()

    Math.asin(-2);  // NaN
    Math.asin(-1);  // -1.5707963267948966 (-pi/2)
    Math.asin(0);   // 0
    Math.asin(0.5); // 0.5235987755982989
    Math.asin(1);   // 1.570796326794897 (pi/2)
    Math.asin(2);   // NaN
    

    For values less than -1 or greater than 1, Math.asin() returns NaN.

    Specifications

    Specification Status Comment
    ECMAScript 1st Edition. Standard Initial definition. Implemented in JavaScript 1.0.
    ECMAScript 5.1 (ECMA-262)
    The definition of 'Math.asin' in that specification.
    Standard  
    ECMAScript 6 (ECMA-262)
    The definition of 'Math.asin' in that specification.
    Draft  

    Browser compatibility

    Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
    Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
    Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
    Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

    See also

    Document Tags and Contributors

    Contributors to this page: evilpie, Sheppy, Marcoos, fscholz, Mingun, ethertank, fred.wang, Mgjbot, Maian, Dria, Kyodev
    Last updated by: Mingun,