# How do you take the natural logs?

1. Feb 19, 2005

### semidevil

how do you take the natural logs??

I think this is why I can't do my problems, maybe i'm missing some basic concepts.

ok, so let $$L({\theta}) = \theta^{-2n} \prod y e^{-(1/theta)}\sum y$$

taking the natural log, I get

$$ln L(\theta) = -2nln\theta + ln \prod y - 1/\theta \sum yi$$.

I dont know, how did they do that?

and later, I will need to differentate it too, but and I dont know how to do it either. but for that one, how did they do it?

2. Feb 19, 2005

### Fredrik

Staff Emeritus
I can't make sense of what you've written. Indices and parentheses would help. Anyway, whatever that first expression is supposed to be, there's a good chance you will be able to simplify the logarithm considerably by using log(xy)=log x + log y repeatedly.

3. Feb 19, 2005

### dextercioby

That product wrt what is it evaluated...?

Daniel.