Let , , , ... be an infinite sequence of real numbers satisfying the equation for all , where and are two different positive reals.
Can this sequence , , , ... be bounded?
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Let , , , ... be an infinite sequence of real numbers satisfying the equation for all , where and are two different positive reals.
Can this sequence , , , ... be bounded?
*
We have an infinite sequence of real numbers satisfying the recursive relation:
for all , where and are two different positive real numbers. Our goal is to determine whether this sequence can be bounded.
### Step 1: Analyze the recursive relation
The given relation
implies a functional dependency between three consecutive terms of the sequence. Importantly, since is defined as the absolute difference between and , the sequence heavily depends on the initial values and .
### Step 2: Investigate the effect of positive differences
Since and are given as different positive real numbers, we can start by observing:
- If and , then either or .
- Similarly, and implies that .
### Step 3: Recursive impact of differing terms
Because and are distinct, as the sequence progresses:
- If , then , which cannot sustain for all since the sequence starts with non-zero values.
- Given the recursive nature, each serves as a source for subsequent terms, making it improbable for all terms to converge to a single bound due to iterative differences.
### Step 4: Sequence dynamics based on initial conditions
Given that and are positive and different, the sequence infinitely alternates in such a manner that it is impossible for it to stabilize or converge to a bound. The discrepancy between consecutive elements will propagate due to the nature of the absolute difference, thereby causing an unbounded progression along the sequence.
#### Conclusion
Based on the conditions and recursive relation, the sequence cannot be bounded, implying that it will diverge or fluctuate indefinitely without settling within any finite bounds.
Therefore, the sequence is not bounded: