AMC 10A/12A 2025 (Problem 18/12)
The harmonic mean of a collection of numbers is the reciprocal of the arithmetic mean of the reciprocals of the numbers in the collection. For example, the harmonic mean of and is What is the harmonic mean of all the real roots of the 4050th-degree polynomial
Let be the roots of Find
Using Vieta's Formula,
Let be the roots of Find
Using Vieta's Formula,
Let be the roots of Find
Using Vieta's Formula,
Use the definition of the harmonic mean. There are real roots, so
(B)