Esercizi svolti di analisi reale e complessa - Dipartimento di ...
Esercizi svolti di analisi reale e complessa - Dipartimento di ...
Esercizi svolti di analisi reale e complessa - Dipartimento di ...
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γ φɛ ≥ 0 <br />
<br />
x<br />
−∞ x ≤ 0 γ(x) =<br />
φɛdx<br />
+∞<br />
−∞ φɛdx = (−∞, x) ∩ φɛ = ∅<br />
<br />
0<br />
+∞<br />
φɛdx −∞<br />
= 0 <br />
x<br />
−∞ x ≥ ɛ γ(x) =<br />
φɛdx<br />
+∞<br />
−∞<br />
+∞ =<br />
φɛdx −∞ φɛdx<br />
+∞ = 1 <br />
φɛdx −∞<br />
(−∞, x] ⊇ φɛ x<br />
−∞ φɛdx = +∞<br />
<br />
<br />
• x = 0 γ(0) = 0 ∀ k ≥ 1 γ (k) (0) = 0 φɛ C∞ <br />
−∞ φɛdx<br />
[0, ɛ] x = 0 <br />
<br />
<br />
<br />
• x = ɛ γ(ɛ) = 1 ∀ k ≥ 1 γ (k) (0) = 0 φɛ C ∞ <br />
[0, ɛ] x = ɛ <br />
<br />
<br />
<br />
<br />
<br />
≡ 0 ≡ 1 <br />
<br />
<br />
(⇒) : M(t) ∀ i, j Mij(t) <br />
∀ ɛ > 0 , ∃ δij |Mij(t) − Mij(t0)| < ɛ , ∀ |t − t0| <<br />
δij δ = mini,j δij <br />
(⇐) : ∀ i, j |Mij(t) − Mij(t0)| < M(t) − M(t0)<br />
f ∈ C ∞ ({y0}, R 2 )<br />
<br />
f ′ (y0) =<br />
1 + 2y1 cos y2 −y 2 1 sin y2<br />
2y1<br />
1<br />
<br />
|y0=(0,0)<br />
=<br />
1 0<br />
0 1<br />
det f ′ (y0) = 1 = 0 ⇒ ∃! f <br />
C ∞ ({f(y0)}, R 2 )