Q:

how to use ln in Java

I'm trying to use this formula in JAVA :  (-ln(1-L))/L
I'm not sure how to use ln in java.

A:

Math.log(d) returns the natural logarithm (base e) of a double value. 
So the java code will be,
double result = (-Math.log(1-L))/L;

(but note that it's better to have variable names in lower-case - i.e. l instead of L)

A:

I also had no idea, but since it's a common math function, I checked the Math class in the API.
Here you go: the log method
EDIT: Sorry for broken link, Markdown is fixed now.  Also I realized right after I posted this answer that it sounds snarky, which was not my intent; re-wordings just make it seems snarky AND sarcastic, though.  I just wanted to make the point that the API really is useful for methods that could be reasonably expected to come up a lot.

