How can I find logarithm of numbers to base?

Question

I want to use dynamic base for logarithm in JavaScript.

ex: logarithm number 16 and base 5 then output should be 1.722706232

How to archive this using JavaScript?

I know how to archive this for base 10. Here is the code for number 16 and base 10

console.log(Math.log10(16));

https://stackoverflow.com/a/18874451/1169798 – Sirko Jul 05 '18 at 13:15 — Sirko, Jul 05 '18 at 13:15

score 4 · Answer 1 · answered Jul 05 '18 at 13:15

4

Use Math.log(), Divide the logarithm of the number with the logarithm of the desired base.

console.log(Math.log(16)/Math.log(5));

answered Jul 05 '18 at 13:15

Satpal

it should be base 10 i think. Math.log10(number)/Math.log10(base); – Oguz Nov 23 '21 at 07:58

score 1 · Answer 2 · answered Jul 05 '18 at 13:16

1

log_n(x) = log_e(x) / log_e(n)

so

function generalLog(n, x) {
   return Math.log(x) / Math.log(n);
}

answered Jul 05 '18 at 13:16

Pointy

score 0 · Answer 3 · edited Jul 05 '18 at 16:51

0

You can use simple mathematics to do this:

 log_y (x) = log_10 (x) / log_10 (y)

edited Jul 05 '18 at 16:51

Bharata

answered Jul 05 '18 at 13:15

3 Answers3