@acer 

I do advanced trigonmetry and pre-calculus. What is LambertW and how does it apply to this situation?

Say I plug some numbers in. In your picture; rt LambertW(.

say r = 0.05 and t = 8.      0.05 * 8 ( then the parenthesis). Can I disreagrd the LambertW part? I appreciate the quick response..

thanks