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theorem proved term proof

rs_cost_satisfies_dalembert

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formal statement (Lean)

  67theorem rs_cost_satisfies_dalembert :
  68    SatisfiesDAlembert (fun t => Cost.Jcost (Real.exp t) + 1) := by

proof body

Term-mode proof.

  69  intro t u
  70  simp only [Cost.Jcost_exp_cosh]
  71  rw [Real.cosh_add, Real.cosh_sub]
  72  ring
  73
  74/-- cosh has no real zeros: cosh(t) ≥ 1 for all t ∈ ℝ. -/

used by (2)

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depends on (10)

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