− − () = + ln () + Δ ̅ () = − () = Δ ̅ () = − () = 0 − ( = 0) = + ln − ( = 0) Δ ̅ − − () = ( = 0) ∙ (− ) − ( = 0) = , , , () = (− Δ ̅ ) ∆ ℎ ℎ ≅ 1