theorem
proved
term proof
jcost_pos_away_from_one
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formal statement (Lean)
63theorem jcost_pos_away_from_one {x : ℝ} (hx : 0 < x) (hne : x ≠ 1) :
64 0 < Jcost x := Jcost_pos_of_ne_one x hx hne
proof body
Term-mode proof.
65
66/-- **F1.1.6**: J(1) = 0 and the second derivative at 1 gives unit curvature.
67 We state this via the quadratic approximation. -/