theorem
proved
tactic proof
cos_satisfies_axioms
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formal statement (Lean)
355theorem cos_satisfies_axioms : AngleCouplingAxioms Real.cos where
356 dAlembert := cos_dAlembert
proof body
Tactic-mode proof.
357 continuous := Real.continuous_cos
358 normalized := Real.cos_zero
359 calibrated := by
360 have h : deriv (deriv (fun x => Real.cos x)) 0 = -Real.cos 0 := cos_second_deriv_eq 0
361 rw [h]
362 simp [Real.cos_zero]
363
364/-- cos satisfies standard regularity. -/