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lemma proved term proof

exp_048_lt_phi

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formal statement (Lean)

 189private lemma exp_048_lt_phi : exp_taylor_10_at_048 + exp_error_10_at_048 < 161803395 / 100000000 := by

proof body

Term-mode proof.

 190  native_decide
 191
 192/-- Rigorous lower bound: log(φ) > 0.48
 193
 194    Proof using exp monotonicity: log(φ) > 0.48 ↔ φ > exp(0.48).
 195    We have φ > 1.61803395 and exp(0.48) ≈ 1.6160... < 1.61803395. -/

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