Math Constants in JavaScript: Math.E, Math.PI, and more

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Question: How do I handle mathematical constants in JavaScript?

Answer: In JavaScript, some mathematical constants are predefined – they are properties of the

Math
object. You can write these constants as follows:
Math.PI      // pi = 3.14159265...
Math.E       // e = 2.71828182...
Math.LOG2E   // log of e base 2
Math.LOG10E  // log of e base 10
Math.LN2     // log of 2 base e
Math.LN10    // log of 10 base e
Math.SQRT2   // square root of 2
Math.SQRT1_2 // square root of 1/2
Thus, there is no need to remember the exact value of e or π. Just use
Math.E
or
Math.PI
! Here is a simple code example that computes the radius of the Earth in kilometers and in miles using
Math.PI
:
var rkm = 20000/Math.PI;
var rmi = 20000/(1.609344*Math.PI);

document.write(
  "The Earth's radius is "
 +rkm.toFixed()+" km, or "
 +rmi.toFixed()+" miles. "
);
This code produces the following output:

See also:

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