theorem
proved
term proof
phi_inv3_lt
show as:
view Lean formalization →
formal statement (Lean)
427theorem phi_inv3_lt : goldenRatio⁻¹ ^ 3 < (0.237 : ℝ) := by
proof body
Term-mode proof.
428 have h1 := phi_inv_lt
429 have h2 := phi_inv2_lt
430 have hpos : 0 < goldenRatio⁻¹ := inv_pos.mpr goldenRatio_pos
431 nlinarith [sq_nonneg goldenRatio⁻¹]
432
433/-- Interval containing (φ⁻¹)³ - PROVEN -/