I have a conditional recurrence relational, that is conditioned on a function value (defined on sequence index).
$ X_{i+1} = \begin{cases} X_{i} + a_1. b^i ,& \text{if } X_i \geq c. b^i\\ X_{i} + a_2. b^i, & \text{otherwise} \end{cases} $
where $a_1, a_2, c, b$ are constants.
I am at large as to how to try to solve the problem. Further, I know that $a_1, a_2$ control the rate of change of $X$ such that it remains close to $c. b^i$.