I would like to find the $\displaystyle n$ that maximizes this discrete function

$\displaystyle d(n) = \frac{R^{n+1}}{\sin(\theta)}\left[R\sin(\theta(n+1)) - \sin(\theta(n+2))\right]$

where n is 0,1,2,....

$\displaystyle 0<R<1$ and $\displaystyle 0<\theta < \pi $

Is that even possible?