Compfiles: Catalog Of Math Problems Formalized In Lean

Usa1978P1


import Mathlib.Tactic

/-!
# USA Mathematical Olympiad 1978, Problem 1

Given that a,b,c,d,e are real numbers such that

  a  + b  + c  + d  + e  = 8
  a² + b² + c² + d² + e² = 16,

determine the maximum value of e.
-/

namespace Usa1978P1

noncomputable /- determine -/ abbrev max_e : ℝ := sorry

abbrev IsGood (a b c d e : ℝ) : Prop :=
  a + b + c + d + e = 8 ∧ a^2 + b^2 + c^2 + d^2 + e^2 = 16

theorem usa1978_p1 :
    IsGreatest { e : ℝ | ∃ a b c d : ℝ, IsGood a b c d e } max_e := sorry

This problem has a complete formalized solution written by Hongyu Ouyang.

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