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Math.asin()

The Math.asin() static method returns the inverse sine (in radians) of a number. That is,

βˆ€ x ∊ [ βˆ’ 1 , 1 ] , π™ΌπšŠπšπš‘.πšŠπšœπš’πš— ( 𝚑 ) = arcsin ( x ) = the unique y ∊ [ βˆ’ Ο€ 2 , Ο€ 2 ] such that sin ( 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

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Syntax

js
Math.asin(x)

Parameters

x

A number between -1 and 1, inclusive, representing the angle's sine value.

Return value

The inverse sine (angle in radians between - Ο€ 2 -\frac{\pi}{2} and Ο€ 2 \frac{\pi}{2} , inclusive) of x. If x is less than -1 or greater than 1, returns NaN.

Description

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

Using Math.asin()

js
Math.asin(-2); // NaN
Math.asin(-1); // -1.5707963267948966 (-Ο€/2)
Math.asin(-0); // -0
Math.asin(0); // 0
Math.asin(0.5); // 0.5235987755982989 (Ο€/6)
Math.asin(1); // 1.5707963267948966 (Ο€/2)
Math.asin(2); // NaN

Specifications

Browser compatibility

Desktop Mobile Server
Chrome Edge Firefox Opera Safari Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet WebView Android Deno Node.js
asin 1 12 1 3 1 18 4 10.1 1 1.0 4.4 1.0 0.10.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/asin