A normalized cubic sum with a pairwise quadratic correction
ProvedWorkbookSource.base_6962lean-workbooksource-checked
Let a,b,c>0 Prove that: I know it's easy but It is nice. It's must be like this:
Source: InternLM Lean-Workbook, record lean_workbook_6962 (Apache-2.0). Complete source proposition preserved; proof developed independently.
Preamble
import Mathlib open Real Nat
Formal statement
theorem WorkbookSource.base_6962 (a b c : ℝ) (ha : 0 < a) (hb : 0 < b) (hc : 0 < c) : (a^3 + b^3 + c^3) / (a * b * c) + 9 * (a * b + b * c + c * a) / (a^2 + b^2 + c^2) ≥ 12 := by sorry
Source