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author | Anton Luka Šijanec <anton@sijanec.eu> | 2024-06-26 23:53:15 +0200 |
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committer | Anton Luka Šijanec <anton@sijanec.eu> | 2024-06-26 23:53:15 +0200 |
commit | 3d538747f57492600479309a14fac2276c8ce8e8 (patch) | |
tree | 7f4572925a356a85dfc4e7bec788a1cd5f9699e8 /šola/ana2/teor.lyx | |
parent | vremenska postaja (diff) | |
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diff --git a/šola/ana2/teor.lyx b/šola/ana2/teor.lyx new file mode 100644 index 0000000..e1ee169 --- /dev/null +++ b/šola/ana2/teor.lyx @@ -0,0 +1,864 @@ +#LyX 2.4 created this file. For more info see https://www.lyx.org/ +\lyxformat 620 +\begin_document +\begin_header +\save_transient_properties true +\origin unavailable +\textclass article +\begin_preamble +\usepackage{hyperref} +\usepackage{siunitx} +\usepackage{pgfplots} +\usepackage{listings} +\usepackage{multicol} +\sisetup{output-decimal-marker = {,}, quotient-mode=fraction, output-exponent-marker=\ensuremath{\mathrm{3}}} +\usepackage{amsmath} +\usepackage{tikz} +\newcommand{\udensdash}[1]{% + \tikz[baseline=(todotted.base)]{ + \node[inner sep=1pt,outer sep=0pt] (todotted) {#1}; + \draw[densely dashed] (todotted.south west) -- (todotted.south east); + }% +}% +\DeclareMathOperator{\Lin}{Lin} +\DeclareMathOperator{\rang}{rang} +\DeclareMathOperator{\sled}{sled} +\DeclareMathOperator{\Aut}{Aut} +\DeclareMathOperator{\red}{red} +\DeclareMathOperator{\karakteristika}{char} +\usepackage{algorithm,algpseudocode} +\providecommand{\corollaryname}{Posledica} +\end_preamble +\use_default_options true +\begin_modules +enumitem +theorems-ams +\end_modules +\maintain_unincluded_children no +\language slovene +\language_package default +\inputencoding auto-legacy +\fontencoding auto +\font_roman "default" "default" +\font_sans "default" "default" +\font_typewriter "default" "default" +\font_math "auto" "auto" +\font_default_family default +\use_non_tex_fonts false +\font_sc false +\font_roman_osf false +\font_sans_osf false +\font_typewriter_osf false +\font_sf_scale 100 100 +\font_tt_scale 100 100 +\use_microtype false +\use_dash_ligatures true +\graphics default +\default_output_format default +\output_sync 0 +\bibtex_command default +\index_command default +\paperfontsize default +\spacing single +\use_hyperref false +\papersize default +\use_geometry true +\use_package amsmath 1 +\use_package amssymb 1 +\use_package cancel 1 +\use_package esint 1 +\use_package mathdots 1 +\use_package mathtools 1 +\use_package mhchem 1 +\use_package stackrel 1 +\use_package stmaryrd 1 +\use_package undertilde 1 +\cite_engine basic +\cite_engine_type default +\biblio_style plain +\use_bibtopic false +\use_indices false +\paperorientation portrait +\suppress_date false +\justification false +\use_refstyle 1 +\use_formatted_ref 0 +\use_minted 0 +\use_lineno 0 +\index Index +\shortcut idx +\color #008000 +\end_index +\leftmargin 2cm +\topmargin 2cm +\rightmargin 2cm +\bottommargin 2cm +\headheight 2cm +\headsep 2cm +\footskip 1cm +\secnumdepth 3 +\tocdepth 3 +\paragraph_separation indent +\paragraph_indentation default +\is_math_indent 0 +\math_numbering_side default +\quotes_style german +\dynamic_quotes 0 +\papercolumns 1 +\papersides 1 +\paperpagestyle default +\tablestyle default +\tracking_changes false +\output_changes false +\change_bars false +\postpone_fragile_content false +\html_math_output 0 +\html_css_as_file 0 +\html_be_strict false +\docbook_table_output 0 +\docbook_mathml_prefix 1 +\end_header + +\begin_body + +\begin_layout Title +ANA2 IŠRM 2023/24 +\end_layout + +\begin_layout Author + +\noun on +Anton Luka Šijanec +\end_layout + +\begin_layout Date +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +today +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Section +Množice v +\begin_inset Formula $\mathbb{R}^{n}$ +\end_inset + + +\end_layout + +\begin_layout Definition* +Razdalja točk v +\begin_inset Formula $\mathbb{R}^{n}$ +\end_inset + + je norma njune razlike. + +\begin_inset Formula $\varepsilon-$ +\end_inset + +okolica točke +\begin_inset Formula $a\in\mathbb{R}^{n}$ +\end_inset + + so take točke, + ki so od +\begin_inset Formula $a$ +\end_inset + + oddaljene manj od +\begin_inset Formula $\varepsilon\in\mathbb{R}$ +\end_inset + +. + Robna točka množice +\begin_inset Formula $A$ +\end_inset + + je taka točka, + katere poljubno majhna okolica vsebuje tako točke iz +\begin_inset Formula $A$ +\end_inset + + kot tudi točke, + ki niso iz +\begin_inset Formula $A$ +\end_inset + +. + Odprta množica ne vsebuje robnih točk. + Zaprta množica je komplement neke odprte množice. +\end_layout + +\begin_layout Claim* +\begin_inset Formula $A\subset\mathbb{R}$ +\end_inset + + zaprta +\begin_inset Formula $\Leftrightarrow$ +\end_inset + + za vsako zaporedje s členi v +\begin_inset Formula $A$ +\end_inset + + velja, + da so vsa njegova stekališča, + čim obstajajo, + v +\begin_inset Formula $A$ +\end_inset + +. +\end_layout + +\begin_layout Proof +Dokazujemo ekvivalenco +\end_layout + +\begin_deeper +\begin_layout Description +\begin_inset Formula $\left(\Rightarrow\right)$ +\end_inset + + Naj bo +\begin_inset Formula $s$ +\end_inset + + stekališče +\begin_inset Formula $\left(a_{n}\right)_{n\in\mathbb{N}}$ +\end_inset + +, + +\begin_inset Formula $a_{n}\in A$ +\end_inset + + in +\begin_inset Formula $s\not\in A$ +\end_inset + + (RAAPDD). + Ker je +\begin_inset Formula $A$ +\end_inset + + zaprta, + je +\begin_inset Formula $\mathbb{R}\setminus A$ +\end_inset + + odprta, + zato +\begin_inset Formula $\exists\varepsilon>0\ni:\left(s-\varepsilon,s+\varepsilon\right)\subset\mathbb{R}\setminus A$ +\end_inset + +, + torej v +\begin_inset Formula $\left(s-\varepsilon,s+\varepsilon\right)$ +\end_inset + + ni nobenega člena zaporedja, + torej +\begin_inset Formula $s$ +\end_inset + + ni stekališče +\begin_inset Formula $\rightarrow\!\leftarrow$ +\end_inset + +. +\end_layout + +\begin_layout Description +\begin_inset Formula $\left(\Leftarrow\right)$ +\end_inset + + Dokazujemo, + da je +\begin_inset Formula $A$ +\end_inset + + zaprta, + torej, + da je +\begin_inset Formula $B=\mathbb{R}\setminus A$ +\end_inset + + odprta. + PDDRAA +\begin_inset Formula $B$ +\end_inset + + ni odprta +\begin_inset Formula $\Rightarrow\exists x\in B\ni:\forall n\in\mathbb{N}:$ +\end_inset + + +\begin_inset Formula $n^{-1}-$ +\end_inset + +okolica +\begin_inset Formula $x$ +\end_inset + + vsebuje nek element +\begin_inset Formula $A$ +\end_inset + +. + Našli smo torej zaporedje v +\begin_inset Formula $A$ +\end_inset + + s stekališčem v +\begin_inset Formula $B$ +\end_inset + +. + +\begin_inset Formula $\rightarrow\!\leftarrow$ +\end_inset + +. +\end_layout + +\end_deeper +\begin_layout Definition* +Stroga podmnožica +\begin_inset Formula $\mathbb{R}$ +\end_inset + + je kompaktna, + če ima vsako zaporedje s členi v njej v njej tudi stekališče. + Množica je omejena, + če je podmnožica neke okolice izhodišča. +\end_layout + +\begin_layout Theorem* +\begin_inset Formula $A\subset\mathbb{R}$ +\end_inset + + kompaktna +\begin_inset Formula $\Leftrightarrow A$ +\end_inset + + zaprta in omejena. +\end_layout + +\begin_layout Proof +Dokazujemo ekvivalenco +\end_layout + +\begin_deeper +\begin_layout Labeling +\labelwidthstring 00.00.0000 +\begin_inset Formula $\left(\Leftarrow\right)$ +\end_inset + + Naj bo +\begin_inset Formula $\left(a_{n}\right)_{n\in\mathbb{N}}$ +\end_inset + + zaporedje v +\begin_inset Formula $A$ +\end_inset + +. + Ker je +\begin_inset Formula $A$ +\end_inset + + omejena, + je zaporedje omejeno, + torej premore stekališča. + Ker je +\begin_inset Formula $A$ +\end_inset + + zaprta, + vsebuje vsa ta stekališča. + Torej je +\begin_inset Formula $A$ +\end_inset + + kompaktna. +\end_layout + +\begin_layout Labeling +\labelwidthstring 00.00.0000 +\begin_inset Formula $\left(\Rightarrow\right)$ +\end_inset + + +\begin_inset Formula $A$ +\end_inset + + je omejeno, + sicer bi našli zaporedje, + da velja +\begin_inset Formula $a_{i}\geq i$ +\end_inset + +, + ki nima stekališča. + Treba je dokazati še, + da je +\begin_inset Formula $A$ +\end_inset + + zaprta. + Vsa stekališča zaporedij s členi v +\begin_inset Formula $A$ +\end_inset + + imajo v +\begin_inset Formula $A$ +\end_inset + + stekališče (kompaktnost). + Torej za vsako stekališče zaporedja s členi v +\begin_inset Formula $A$ +\end_inset + + velja, + da ima v +\begin_inset Formula $A$ +\end_inset + + stekališče, + torej je +\begin_inset Formula $A$ +\end_inset + + zaprta. +\end_layout + +\end_deeper +\begin_layout Remark* +Vsako zaporedje v kompaktni množici ima stekališče, + kar za zaprto množico ni rečeno. + Zaprta množica lahko vsebuje zaporedja brez stekališč. +\begin_inset Note Note +status open + +\begin_layout Plain Layout +razloži normo, + trikotniško neenakost, + itd. +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Definition* +Točka +\begin_inset Formula $a\in A\subseteq\mathbb{R}^{n}$ +\end_inset + + je notranja, + če obstaja neka njena okolica, + ki je podmnožica +\begin_inset Formula $A$ +\end_inset + +. + Točka +\begin_inset Formula $a\in\mathbb{R}^{n}$ +\end_inset + + je stekališče množice +\begin_inset Formula $A$ +\end_inset + +, + če vsaka njena okolica seka +\begin_inset Foot +status open + +\begin_layout Plain Layout +t. + j. + ima neprazen presek z +\end_layout + +\end_inset + + +\begin_inset Formula $A\setminus\left\{ a\right\} $ +\end_inset + +. + Točka +\begin_inset Formula $a\in A$ +\end_inset + +, + ki ni stekališče +\begin_inset Formula $A$ +\end_inset + +, + je izolirana točka +\begin_inset Formula $A$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset Separator plain +\end_inset + + +\end_layout + +\begin_layout Definition* +Zaporedje s členi v +\begin_inset Formula $\mathbb{R}^{k}$ +\end_inset + + je funkcija +\begin_inset Formula $\mathbb{N}\to\mathbb{R}^{k}$ +\end_inset + +, + +\begin_inset Formula $n\mapsto a_{n}=\left(a_{n}^{\left(1\right)},\dots,a_{n}^{\left(k\right)}\right)$ +\end_inset + +. + +\begin_inset Formula $a\in\mathbb{R}^{k}$ +\end_inset + + je limita zaporedja +\begin_inset Formula $\left(a_{n}\right)_{n}$ +\end_inset + + s členi v +\begin_inset Formula $\mathbb{R}^{k}$ +\end_inset + +, + če +\begin_inset Formula $\forall\varepsilon>0\exists n_{0}\in\mathbb{N}\forall n>n_{0}:\left|a-a_{n}\right|<\varepsilon$ +\end_inset + + in pišemo +\begin_inset Formula $a=\lim_{n\to\infty}a_{n}$ +\end_inset + +. + Če zaporedje ima limito, + je konvergentno, + sicer je divergentno. + Točka +\begin_inset Formula $s\in\mathbb{R}^{k}$ +\end_inset + + je stekališče zaporedja +\begin_inset Formula $\left(a_{n}\right)_{n}$ +\end_inset + + s členi v +\begin_inset Formula $\mathbb{R}^{k}$ +\end_inset + +, + če je v vsaki okolici +\begin_inset Formula $s$ +\end_inset + + neskončno členov +\begin_inset Formula $\left(a_{n}\right)_{n}$ +\end_inset + +. +\end_layout + +\begin_layout Fact* +Velja: +\end_layout + +\begin_deeper +\begin_layout Itemize +Vsako konvergentno zaporedje je omejeno in ima natanko eno limito, + ki je njegovo edino stekališče. +\end_layout + +\begin_layout Itemize +Vsako omejeno zaporedje ima stekališče. +\end_layout + +\begin_layout Itemize +Stekališče zaporedja je limita nekega podzaporedja in obratno. +\end_layout + +\begin_layout Itemize +\begin_inset Formula $A\subset\mathbb{R}^{k}$ +\end_inset + + je zaprta +\begin_inset Formula $\Leftrightarrow$ +\end_inset + + vsako stekališče zaporedja s členi v +\begin_inset Formula $A$ +\end_inset + + leži v +\begin_inset Formula $A$ +\end_inset + +. +\end_layout + +\end_deeper +\begin_layout Section +Funkcije več spremenljivk +\end_layout + +\begin_layout Definition* +Naj bo +\begin_inset Formula $D\subseteq\mathbb{R}^{k}$ +\end_inset + + in +\begin_inset Formula $f:D\to\mathbb{R}$ +\end_inset + + preslikava. + Če je +\begin_inset Formula $k\geq2$ +\end_inset + +, + je +\begin_inset Formula $f$ +\end_inset + + funkcija več spremenljivk. + +\begin_inset Formula $\Gamma_{f}=\left\{ \left(x,fx\right);x\in D\right\} \subset\mathbb{R}^{k}\times\mathbb{R}$ +\end_inset + + je graf funkcije +\begin_inset Formula $f$ +\end_inset + +. + Za +\begin_inset Formula $a\in\mathbb{R}^{k}$ +\end_inset + + stekališče +\begin_inset Formula $D$ +\end_inset + + je +\begin_inset Formula $L\in\mathbb{R}$ +\end_inset + + limita +\begin_inset Formula $f$ +\end_inset + + v +\begin_inset Formula $a$ +\end_inset + +, + če +\begin_inset Formula $\forall\varepsilon>0\exists\delta=\delta\left(a,\varepsilon\right)>0\forall x\in D,x\not=a:\left|\left|x-a\right|\right|<\delta\Rightarrow\left|fx-L\right|<\varepsilon$ +\end_inset + + in pišemo +\begin_inset Formula $\lim_{x\to a}fx=L$ +\end_inset + +. +\end_layout + +\begin_layout Remark* +Medtem ko imamo pri funkcijah ene spremenljivke levo in desno limito, + je tu obnašanje bolj zapleteno, + saj obstaja veliko različnih načinov približevanja k +\begin_inset Formula $a$ +\end_inset + +. +\end_layout + +\begin_layout Definition* +Naj bo +\begin_inset Formula $D\subseteq\mathbb{R}^{k}$ +\end_inset + + in +\begin_inset Formula $f:D\to\mathbb{R}$ +\end_inset + + funkcija in +\begin_inset Formula $a\in D$ +\end_inset + +. + +\begin_inset Formula $f$ +\end_inset + + je zvezna v +\begin_inset Formula $a$ +\end_inset + +, + če +\begin_inset Formula $\forall\varepsilon>0\exists\delta=\delta\left(a,\varepsilon\right)>0\forall x\in D:\left|\left|x-a\right|\right|<\delta\Rightarrow\left|fx-fa\right|<\varepsilon$ +\end_inset + +. + +\begin_inset Formula $f$ +\end_inset + + je zvezna, + če je zvezna na vsaki točki svojega definicijskega območja. +\end_layout + +\begin_layout Remark* +Če je +\begin_inset Formula $a$ +\end_inset + + stekališče +\begin_inset Formula $D$ +\end_inset + +, + je +\begin_inset Formula $f$ +\end_inset + + zvezna v +\begin_inset Formula $a\Leftrightarrow\lim_{x\to a}fx=fa$ +\end_inset + +. +\end_layout + +\begin_layout Corollary* +Če je +\begin_inset Formula $a$ +\end_inset + + izolirana točka +\begin_inset Formula $D$ +\end_inset + +, + je +\begin_inset Formula $f$ +\end_inset + + zvezna v +\begin_inset Formula $a$ +\end_inset + +. +\end_layout + +\begin_layout Definition* +Naj bo +\begin_inset Formula $f:D\subseteq\mathbb{R}^{k}\to\mathbb{R}$ +\end_inset + + funkcija, + +\begin_inset Formula $Z=fD$ +\end_inset + + njena zaloga vrednosti in +\begin_inset Formula $g:Z\to\mathbb{R}$ +\end_inset + + funkcija. + Kompozitum ali sestavljena funkcija +\begin_inset Formula $f$ +\end_inset + + in +\begin_inset Formula $g$ +\end_inset + + je funkcija +\begin_inset Formula $k$ +\end_inset + + spremenljivk +\begin_inset Formula $g\circ f:D\to\mathbb{R}$ +\end_inset + +, + definirana s predpisom +\begin_inset Formula $\left(g\circ f\right)x=gfx$ +\end_inset + +. +\end_layout + +\begin_layout Theorem* +Naj bo +\begin_inset Formula $f$ +\end_inset + + funkcija +\begin_inset Formula $k$ +\end_inset + + spremenljivk, + zvezna v +\begin_inset Formula $a\in\mathbb{R}^{k}$ +\end_inset + + in +\begin_inset Formula $g$ +\end_inset + + funkcija ene spremenljivke, + zvezna v +\begin_inset Formula $fa\in\mathbb{R}$ +\end_inset + +. + Tedaj je +\begin_inset Formula $g\circ f$ +\end_inset + + zvezna v +\begin_inset Formula $a$ +\end_inset + +. +\end_layout + +\begin_layout Proof +Izberimo poljuben +\begin_inset Formula $\varepsilon$ +\end_inset + + +\end_layout + +\end_body +\end_document 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