The equation has as one of the roots. If the other two roots are real, then the minimum possible non-negative integer value of is
The equation has as one of the roots. If the other two roots are real, then the minimum possible non-negative integer value of is
Entered answer:
Solution
We need to find the value of when one root is and the other two roots are real.
Let us work through this using Vieta's formulas - these connect the coefficients of a polynomial to sums and products of its roots.
For the cubic , if the three roots are , , and :
Product of all roots:
This gives us:
Sum of all roots:
This gives us:
Since and are real numbers with , we need to find when this is possible.
Key insight: When two real numbers have a positive product, they're either both positive or both negative.
If both are positive: Using AM-GM inequality,
If both are negative: Then
Therefore: or
Substituting :
Case 1:
Case 2:
So: or
Since we need non-negative integer values, only is relevant.
The minimum non-negative integer satisfying is .
Let us check :
The quadratic with roots is:
Discriminant
Since the discriminant is positive, both roots are real.
Therefore, the minimum possible non-negative integer value of is .
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