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## Doh!

Well, today I had one of those seriously annoying “derrr…. what’s going on???” moments for something that should be so utterly basic (at least I think it is basic).

It was a simple algebra step (when working with the closed form of a linear recurrence sequence) that tripped me up. I just sat there trying to figure out what just happened and why I could not figure it out.

From this: $x_n={r^{n-1}a+(\frac{r^{n-1}-1}{r-1})d}$

To this:     $x_n={(a+\frac{d}{r-1})r^{n-1}-\frac{d}{r-1}}$

I think I need a quick review of algebra. This should be child’s play to me! *cry*

P.S. I did actually figure it out before posting this, I just thought that I would post my pains to the world.