02.06.2013 Views

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 ...

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

• <br />

| sin(x1x4)| ≤ |x1x4| ≤ |x| 2 ≤ δ 2 ;<br />

| sin t| ≤ |t| t ∈ R |xi| ≤ |x| <br />

i = 1, 2, 3, 4<br />

<br />

<br />

<br />

<br />

|f(x) − f(0)| = <br />

1<br />

<br />

− 1, sin(x1x4) ≤<br />

1 + |x|<br />

≤ √ <br />

<br />

1 <br />

2 max − 1<br />

1 + |x| , | sin(x1x4)| ≤<br />

≤ √ 2 max δ, δ 2 .<br />

δ ≤ 1 <br />

<br />

|f(x) − f(0)| ≤ √ 2 max δ, δ 2 =<br />

δ(ε) = min<br />

= √ 2δ .<br />

<br />

<br />

ε<br />

√2 , 1 .<br />

f : E ⊂ R n → R m<br />

f(x) = (f1(x), . . . , fm(x)) x0 ∈ E <br />

f x0 ⇐⇒ fi x0 ∀ i = 1, . . . , m .<br />

<br />

<br />

<br />

<br />

<br />

(=⇒) f x0 <br />

∀ ε > 0 ∃ δ = δ(ε) > 0 : |x − x0| < δ =⇒ |f(x) − f(x0)| < ε .<br />

i = 1, . . . , m<br />

|fi(x) − fi(x0)| ≤ |f(x) − f(x0)|

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!