The cos()
method computes the trigonometric cosine of the specified angle and returns it.
Example
// cosine of the angle 1
let value = Math.cos(1);
console.log(value);
// Output: 0.5403023058681398
cos() Syntax
The syntax of the Math.cos()
method is:
Math.cos(angle)
Here, cos()
is a static method. Hence, we are accessing the method using the class name, Math
.
cos() Parameter
The cos()
method takes a single parameter:
angle
- in radians whose cosine value is to be calculated
cos() Return Value
The cos()
method returns:
- cosine value of the given
angle
(in radians) - NaN (Not a Number) for a non-numeric argument
Example 1: JavaScript Math.cos()
// cosine of 5 radians
let value1 = Math.cos(5);
console.log(value1);
// negative radians are allowed
let value2 = Math.cos(-2);
console.log(value2);
// Output:
// 0.28366218546322625
// -0.4161468365471424
In the above example,
Math.cos(5)
- computes the cosine value of the angle 5Math.cos(-2)
- computes the cosine value of the angle -2
Example 2: Math.cos() with Math Constants
// math constants as arguments
let value3 = Math.cos(Math.PI);
console.log(value3);
// Output: -1
In the above example, we have used the cos()
method to compute the cosine of the math constant PI
.
Example 3: Math.cos() with Non-Numeric argument
let string = "Darth Vader";
// cos() with string as argument
let value = Math.cos(string);
console.log(value);
// Output:
// NaN
In the above example, we have tried to calculate the cosine value of the string "Darth Vader"
resulting in NaN as the output.
Example 4: Math.cos() with Infinity
// infinity as argument
let value1 = Math.cos(Infinity);
console.log(value1);
// negative infinity as argument
let value2 = Math.cos(-Infinity);
console.log(value2);
// Output:
// NaN
// NaN
The cos()
method doesn't treat infinity as a number so the method returns NaN with this argument.
Also, the cosine of an infinite angle is indefinite, which can't be defined with a number.
Recommended readings: