**1. The problem statement, all variables and given/known data**

Guys, could you please help me solve this equation for x:

[itex]220000=\sqrt{1.4*10^{32}*\left[ln(\frac{6.17*10^{20}+x}{6.17*10^{20}})-\frac{x}{6.17*10^{20}+x}\right]*\frac{1}{x}}[/itex]

It’s supposed to give me the radius of the Milky Way’s dark matter halo. I expect to get a value of around 100 kpc (equation will produce a value in m), although that would assume I didn’t mess up anywhere in deriving it.

Please don’t ask me to show you how I derived it, I mean we can do that, but right now I’d really just like to get a value for x. I just can’t solve it myself, and all online calculators I’ve tried it on have failed.

Can you please help me solve it, it took me all day to get here and now I can’t get the actual value.

Thanks!!

http://ift.tt/1iho9Om