# Inaccuracy of Piecewise function? [duplicate]

I have the following issue and can't find a solution so far.

t1 = 60.0*{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,
33, 34, 35, 36, 37, 38, 39, 40, 41, 42};
T11 = 273.15 + {17.0, 20.5, 22.5, 24.0, 25.5, 27.5, 29.0, 30.5, 32.0,
33.0, 34.5, 36.0, 37.5, 39.0, 40.0, 41.5, 43.0, 44.0, 45.5, 47.0,
48.0, 49.5, 50.5, 52.0, 53.0, 54.0, 55.5, 56.5, 57.5, 58.5, 59.5,
61.0, 62.0, 63.0, 64.5, 65.5, 66.5, 67.5, 68.5, 69.5, 70.5, 71.0,
72};
nlm1 = NonlinearModelFit[Transpose[{t1, T11}],
a*x^2 + b*x + c, {a, b, c}, x, MaxIterations -> 1000];
T1[t_] = Piecewise[{{nlm1[t], t <= Max[t1]}, {nlm1[Max[t1]],
t >= Max[t1]}}];


Then I plot a narrow segment of T1[t]:

Plot[T1[t], {t, 2519.9999, 2520.0001}]


(note that 60*42=2520)

and see this:

I've tried to set Accuracy and Precision of initial data, those parameters of Piecewise function, WorkingPrecision, but with no result. Does anyone know how to solve this?

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## marked as duplicate by ubpdqn, RunnyKine, m_goldberg, rasher, Mr.Wizard♦May 2 '14 at 6:15

Add Exclusions -> None in the Plot :) –  Öskå May 1 '14 at 16:17
Well, as @Öskå wrote, adding Exclusions -> None to Plot is all that was needed.