Lesson 10: JavaScript Math Object

Master mathematical operations in JavaScript with the powerful Math object and interactive examples.

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10.1 Introduction to the Math Object

The JavaScript Math object provides properties and methods for mathematical constants and functions. It allows you to perform mathematical tasks on numbers.

Key features: The Math object allows you to perform common mathematical operations like rounding, trigonometry, exponentiation, logarithms, and more. It also provides mathematical constants like π and e.

Example 10.1: Using Math Methods

// Absolute value
const absValue = Math.abs(-7.25);

// Square root
const sqrtValue = Math.sqrt(64);

// Power function
const powValue = Math.pow(4, 3);

// Rounding functions
const roundValue = Math.round(4.7);
const ceilValue = Math.ceil(4.4);
const floorValue = Math.floor(4.7);

// Trigonometric functions
const sinValue = Math.sin(Math.PI / 2);
const cosValue = Math.cos(Math.PI);

document.write(`Absolute value of -7.25: ${absValue}`);
document.write(`<br>Square root of 64: ${sqrtValue}`);
document.write(`<br>4 raised to power 3: ${powValue}`);
document.write(`<br>Round 4.7: ${roundValue}`);
document.write(`<br>Ceil 4.4: ${ceilValue}`);
document.write(`<br>Floor 4.7: ${floorValue}`);
document.write(`<br>Sine of π/2: ${sinValue}`);
document.write(`<br>Cosine of π: ${cosValue}`);

10.2 Math Methods

The Math object provides numerous methods to perform mathematical operations. Here are some of the most commonly used ones:

Rounding Methods

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Powers & Roots

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Trigonometry

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Min/Max/Random

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Table 10.1: Math Methods
Method Description Example
abs(x) Returns absolute value of x Math.abs(-4.7) → 4.7
ceil(x) Rounds x up to nearest integer Math.ceil(4.4) → 5
floor(x) Rounds x down to nearest integer Math.floor(4.7) → 4
round(x) Rounds x to nearest integer Math.round(4.7) → 5
max(x,y,z,...n) Returns highest-valued number Math.max(0, 150, 30, 20) → 150
min(x,y,z,...n) Returns lowest-valued number Math.min(0, 150, 30, 20) → 0
pow(x,y) Returns x to the power of y Math.pow(8, 2) → 64
sqrt(x) Returns square root of x Math.sqrt(64) → 8
random() Returns random number between 0 and 1 Math.random() → 0.123456
sin(x) Returns sine of x (x in radians) Math.sin(Math.PI/2) → 1
cos(x) Returns cosine of x (x in radians) Math.cos(Math.PI) → -1
tan(x) Returns tangent of x (x in radians) Math.tan(Math.PI/4) → 1

10.3 Math Properties

The Math object also provides several mathematical constants as read-only properties:

Math.PI
3.141592653589793
Ratio of circumference to diameter
Math.E
2.718281828459045
Euler's constant
Math.SQRT2
1.4142135623730951
Square root of 2
Math.SQRT1_2
0.7071067811865476
Square root of 1/2
Math.LN2
0.6931471805599453
Natural log of 2
Math.LN10
2.302585092994046
Natural log of 10
Math.LOG2E
1.4426950408889634
Base 2 log of E
Math.LOG10E
0.4342944819032518
Base 10 log of E
Table 10.2: Math Properties
Property Description Value (approx.)
Math.PI Pi, the ratio of circle circumference to diameter 3.141592653589793
Math.E Euler's constant, base of natural logarithms 2.718281828459045
Math.SQRT2 Square root of 2 1.4142135623730951
Math.SQRT1_2 Square root of 1/2 0.7071067811865476
Math.LN2 Natural logarithm of 2 0.6931471805599453
Math.LN10 Natural logarithm of 10 2.302585092994046
Math.LOG2E Base 2 logarithm of E 1.4426950408889634
Math.LOG10E Base 10 logarithm of E 0.4342944819032518

10.4 Real-World Applications

Math object methods are essential for many real-world applications:

10.4.1: Circle Calculator

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10.4.2: Random Password Generator

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10.4.3: Distance Calculator

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