JavaScript Math Object Methods

The JavaScript Math object is a built-in object that provides mathematical functions and constants. It is not a constructor, so you cannot create instances of it. Instead, you access its methods and properties directly.

Rounding Methods

• Math.round(x) → Rounds x to the nearest integer.
• Math.floor(x) → Rounds x down to the nearest integer.
• Math.ceil(x) → Rounds x up to the nearest integer.
• Math.trunc(x) → Removes the decimal part of x.

Example

const num = 4.7;
console.log(Math.round(num)); // Output: 5 (Rounds to nearest integer)
console.log(Math.floor(num)); // Output: 4 (Rounds down)
console.log(Math.ceil(num));  // Output: 5 (Rounds up)
console.log(Math.trunc(num)); // Output: 4 (Removes decimal part)

Arithmetic Methods

• Math.pow(x, y) → Returns x raised to the power of y.
• Math.sqrt(x) → Returns the square root of x.
• Math.cbrt(x) → Returns the cube root of x.
• Math.abs(x) → Returns the absolute value of x.

Example

const x = -8;
const y = 3;
console.log(Math.pow(x, y));  // Output: -512 (Raises -8 to the power of 3)
console.log(Math.sqrt(16));   // Output: 4 (Square root of 16)
console.log(Math.cbrt(27));   // Output: 3 (Cube root of 27)
console.log(Math.abs(x));     // Output: 8 (Absolute value of -8)

Trigonometric Methods

• Math.sin(x), Math.cos(x), Math.tan(x) → Returns trigonometric values (input in radians).
• Math.asin(x), Math.acos(x), Math.atan(x) → Returns inverse trigonometric values.
• Math.atan2(y, x) → Returns the angle between (x, y) and the x-axis. 

Example

const x = 1;
const y = 1;
console.log(Math.sin(Math.PI / 2));  // Output: 1
console.log(Math.cos(0));            // Output: 1
console.log(Math.tan(Math.PI / 4));  // Output: 1
console.log(Math.asin(1));           // Output: 1.5707963267948966 (π/2)
console.log(Math.acos(0));           // Output: 1.5707963267948966 (π/2)
console.log(Math.atan(1));           // Output: 0.7853981633974483 (π/4)
console.log(Math.atan2(y, x));       // Output: 0.7853981633974483 (π/4) 

Logarithmic and Exponential Methods

• Math.log(x) → Natural logarithm (base e).
• Math.log10(x) → Logarithm base 10.
• Math.log2(x) → Logarithm base 2.
• Math.exp(x) → Returns e^x.

Example

const x = 8;
console.log(Math.log(x));     // Output: 2.0794415416798357  (Natural log of 8)
console.log(Math.log10(x));   // Output: 0.9030899869919435  (Log base 10 of 8)
console.log(Math.log2(x));    // Output: 3                    (Log base 2 of 8)
console.log(Math.exp(2));     // Output: 7.38905609893065     (e^2)

Random and Max/Min Methods

• Math.random() → Returns a random number between 0 and 1.
• Math.max(a, b, c, ...) → Returns the largest number.
• Math.min(a, b, c, ...) → Returns the smallest number.

Example

const randomNum = Math.random();  
const maxNum = Math.max(10, 25, 5, 40, 15);  
const minNum = Math.min(10, 25, 5, 40, 15);  
console.log(randomNum);  // Output: (random value between 0 and 1)
console.log(maxNum);     // Output: 40 (largest number)
console.log(minNum);     // Output: 5 (smallest number)

Generating a Random Number Between min (Inclusive) and max (Exclusive)

The function below returns a random integer where min is included, but max is excluded:

function getRandomInteger(min, max) {
 return Math.floor(Math.random() * (max - min)) + min;
}

// Testing the function
console.log(getRandomInteger(1, 10)); // Output: A random number between 1 and 9
console.log(getRandomInteger(20, 30)); // Output: A random number between 20 and 29

Explanation:

• Math.random() generates a random decimal between 0 and 1.
• Multiplying by (max - min) scales the range.
• Math.floor() rounds down to ensure the number remains within the specified range.
• Finally, min is added so the lowest possible value is min.

Generating a Random Number Between min and max (Both Inclusive)

The function below ensures that both min and max are included in the possible outcomes.

function getRandomIntegerInclusive(min, max) {
 return Math.floor(Math.random() * (max - min + 1)) + min;
}

// Testing the function
console.log(getRandomIntegerInclusive(1, 10)); // Output: A random number between 1 and 10
console.log(getRandomIntegerInclusive(50, 60)); // Output: A random number between 50 and 60

Explanation:

• The key difference here is (max - min + 1), which ensures max is included in the possible results.
• The rest of the function follows the same logic as the previous example.

Common Constants in Math Object

• Math.PI → Approx. 3.14159
• Math.E → Euler’s number (2.718)
• Math.SQRT2 → Square root of 2
• Math.LN2 → Natural log of 2