Math Help - May I have a question?

1. May I have a question?

Hi Masters,

I calculated 0.2 = e^(-x(ln2/700)) to find x.
But, I could not use a calculator also did not have any approximation for the value of ln.
So, I got x = 700(ln5 / ln2).

But the wolfram says the answer is x = 700((ln5+ 2i pi n) / ln2).
Can I ask where 2i pi n came from?
Was I wrong?

Thanks a lot.

2. Re: May I have a question?

Mathematica assumes numbers are complex until you tell it they are real. The complex Log function is periodic w/period 2pi