edit: Oh nuts, embarrassing typo. Should be "...rearranged in terms of y"(adsbygoogle = window.adsbygoogle || []).push({});

Ok, I swear this isn't homework but if it seems too much like homework I'm happy to have it moved there.

So I need to be able to find x given y in:

y = 1/(1+x)^x

Possibly important:

y will always be between 0 and 1 and as y goes from 0 to 1, x goes from infinity to 0.

I don't really know where to start. Is there an exact algebraic solution at all? I need to write an algorithm that will calculate this reliably. The reason I need it is to calculate a sigmoid-like curve based on certain (in my opinion) intuitive inputs. The one remaining problem is inverting this equation!

Thanks to all who help!

- Andrew

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Y = 1/(1+x)^x rearranged in terms of x

**Physics Forums | Science Articles, Homework Help, Discussion**