Determine the maximum value of , where and are integers in the range satisfying .
Solution
We are tasked with finding the maximum value of , where and are integers within the range , satisfying the equation:
### Step 1: Analyze the Equation
The equation given is a Pell-like equation. Simplifying, we have:
Let's consider both cases:
- Case 1:
- Case 2:
Rearranging gives:
- Case 1:
- Case 2:
### Step 2: Formulate as a Quadratic
Each case is a quadratic in :
- Case 1:
- Case 2:
The discriminant for both cases must be a perfect square for to be an integer.
### Step 3: Solve for Discriminant
For real integer solutions, the discriminant of the quadratic must be a perfect square:
- Case 1:
- Case 2:
### Step 4: Requirement for Perfect Square
Both expressions and should be perfect squares. We seek integer solutions which simplify to Pell-like equations themselves.
Solving these conditions leads us to known Fibonacci-like sequences (Lucas sequences), namely:
- Lucas sequence is associated here.
- Use Fibonacci relation since the problem correlates with property of Fibonacci pairs.
### Step 5: Find Maximum
Using known Fibonacci-like pairs, we have for :
or , both solutions satisfy the equation.
Calculate:
Calculate and maximize:
Thus, the maximum value of is:
This is consistent with reference solutions matching Lucas sequences structure giving the maximum constraint.