JavaScript Math.sin()

Examples

let x = Math.sin(3.14);
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Math.sin(0);
Math.sin(Math.PI/6);
Math.sin(Math.PI/2);
Math.sin(Math.PI);
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Math.sin(x) expect x in radians.

To use degrees, convert degrees to radians first.

let radians = degrees * Math.PI/180;
Math.sin(radians);
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Description

The Math.sin() method returns the sine of a number.

The Math.sin() method returns a number between -1 and 1.

The Math.sin() method expects the number in radians.


What is Radians?

Radians is an angle's α amount of rotation b on a circle:

Radian
DegreesPIRadians
00
PI/1800.0175
30°PI/60.52
45°PI/40.79
90°PI/21.57
180°PI3.14
360°PI*26.28



Syntax

Math.sin(x)

Parameters

Parameter Description
x Required.
A number representing radians.

Return Value

Type Description
Number -1 to 1. The sine of the number.
NaN if the parameter is not numeric.

The Pythagoran Therorem

Math.sin(), Math.cos(), and Math.tan() are related to the Pythagorean theorem:

Pythagoras

Theorem: c2 = a2 + b2

The sine Math.sin() to the angle is a / c.

The cosine Math.cos() to the angle is b / c.

The tangent Math.tan() to the angle is a / b.



Browser Support

Math.sin() is an ECMAScript1 (ES1) feature.

ES1 (JavaScript 1997) is fully supported in all browsers:

Chrome Edge Firefox Safari Opera IE
Yes Yes Yes Yes Yes Yes

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