mathjs/docs/reference/functions/cos.md

Function cos

Calculate the cosine of a value.

For matrices, the function is evaluated element wise.

Syntax

math.cos(x)

Parameters

Parameter	Type	Description
x	Number | BigNumber | Boolean | Complex | Unit | Array | Matrix | null	Function input

Returns

Type	Description
Number | BigNumber | Complex | Array | Matrix	Cosine of x

Examples

math.cos(2);                      // returns Number -0.4161468365471422
math.cos(math.pi / 4);            // returns Number  0.7071067811865475
math.cos(math.unit(180, 'deg'));  // returns Number -1
math.cos(math.unit(60, 'deg'));   // returns Number  0.5

var angle = 0.2;
math.pow(math.sin(angle), 2) + math.pow(math.cos(angle), 2); // returns Number ~1

See also

cos, tan