Question

What does ln mean? and also how is it used?

Answer 1

`ln` stands for 'natural logarithm'.

Explanation:

If the term 'logarithm' means anything to you:
On your calculator you find two buttons for them:
The `log` button, where logs are calculated to the base `10`,
and `ln` that calculates logs to the base `e`.

Logs (both kinds) are used for compressing large measuring scales, like the deciBel scale for sound, and also in exponential and periodic functions.