Find the sum of the real roots of the polynomial [i]Proposed by Evan Chen[/i]
Solution
To find the sum of the real roots of the polynomial
we need to analyze the quadratic factors for .
1. Determine the conditions for real roots:
Each quadratic has real roots if and only if its discriminant is non-negative. The discriminant of is given by:
For the quadratic to have real roots, we need:
Since must be an integer, the largest possible value of is 30. Therefore, the quadratics have real roots for .
2. Sum of the roots of each quadratic:
By Vieta's formulas, the sum of the roots of the quadratic equation is given by:
This is true for each from 1 to 30.
3. Total sum of the real roots:
Since there are 30 such quadratics, and each quadratic contributes a sum of 11 for its roots, the total sum of the real roots is:
The final answer is .