Lembit wrote:
> I need help!!!
> What should i do if i want to get out r from this function where i
> already have a and b.
>
> (1(1/(1+r))^b)/r=a is there any logarithm and if there is in what
> library do i find it
I'm too lazy to attempt the algebra at the moment, but looking at it, I'd
say no, there is no formula for that value  you'll have to use numerical
methods to search for a suitable r for a given a and b. For example, you
might use "Newton's Method" to solve this. You'll likely have to look it up
in a numerical methods book or a calculus book.
cd
