Math Methods

• The JavaScript Math object has a lot of useful methods that are worth mentioning.
• To use the Math methods, we don’t have to construct a new Math object.
• All we do is include the Math object name, and then invoke the method, such as:

let roundUp = Math.round(9.8); 
// here we invoked the round method. This would round 9.8 to 10.

• There are a few constants loaded into the JS Math object’s properties.
• A few of these include:
  • 1. PI : Math.PI
  • 2. Euler’s constant : Math.E
  • 3. Natural log base 10: Math.LN10
• More : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math

• The Math object also has many methods, but we will only cover the ones you will likely use most
• If you’d like to see a full list of the Math object’s methods, go to https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math

• 1. Exponents:
  • Syntax: Math.pow(x,y) where x is the base and y is the exponent

let value = Math.pow(5, 2);
let newValue = Math.pow(value, 2);

• 2. Random:
  • Syntax: Math.random()
  • When Math.random() is used without any arguments, it returns a random value between 0 and 1:

console.log("Here is a random number " + Math.random());

• However, we can specify the values we want the random number to be within range of using the next method:

• 3. Floor:
  • Syntax: Math.floor()
  • Math.floor() is used to return the largest whole number that is less than or equal to a specified value. We use this method to get a random whole number within a specific range of numbers, such as 1-10:

let randomNum = Math.floor((Math.random() * 10) + 1);
console.log(randomNum);

• the syntax of using .floor with .random is:
• Math.floor((Math.random * maxRangeValue) + minRangeValue)

console.log("A new random number between 1 and 10 is " + 
  Math.floor((Math.random() * 10) + 1));
console.log("Another random number between 1 and 10 is " + 
  Math.floor((Math.random() * 10) + 1));

• 4. Round:
  • Syntax: Math.round(x) rounds the value x to the nearest whole number

let roundMeUp = Math.round(5.7);
let roundMeDown = Math.round(7.3);

• 5. Exponential Function:
  • Syntax: Math.exp(x) raises E to the x power

let raised = Math.exp(5);

• 6. Absolute Value:
  • Syntax: Math.abs(x) returns the absolute value of the variable or value in parenthesis

let positive = Math.abs(-24343525);
let negative = -24124214;
let absoluteVal = Math.abs(negative / 2);

• 7. Square Root:
  • Syntax: Math.sqrt(x)returns the square root of the value or variable in parenthesis

let sqrt = Math.sqrt(25);
sqrt = Math.pow(sqrt, 2);
console.log(Math.sqrt(sqrt));

• 8. Trigonometric Functions:
  • Syntax:
  • Sin : Math.sin(x)
  • Tan : Math.tan(x)
  • Cos : Math.cos(x)
  • Arcsin : Math.asin(x)
  • Arctan : Math.atan(x)
  • Arccos : Math.acos(x)

• Though there are a number of methods for the Math object that we didn’t cover, you likely won’t need to use them as a beginner programmer. Still, you can read about them here:
• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math
• and:
• https://www.w3schools.com/js/js_math.asp

Exercises

back