$$f(n)=\frac{2}{5}n^{2.5}+\frac{1}{2}n^{1.5}+\frac{1}{8}n^{0.5}+\frac{1}{1920}n^{-1.5}$$
the inverse I need is for all positive integers.
Can someone either tell me how to get this functions inverse, or just give it to me?
All I know about finding inverse is that I'd need just to get $n$ by itself, but have no clue how to go about doing that, if it's even possible. Though if it's not, is there a way to have excel use this formula as if it's already in it's inverse? (I know that addition would be better on another community, but won't change community unless told that the inverse of this is impossible.)