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| author | Juan Marín Noguera <juan@mnpi.eu> | 2025-05-16 22:18:44 +0200 |
|---|---|---|
| committer | Juan Marín Noguera <juan@mnpi.eu> | 2025-05-16 22:18:44 +0200 |
| commit | 4f670b750af5c11e1eac16d9cd8556455f89f46a (patch) | |
| tree | e0f8d7b33df2727d89150f799ee8628821fda80a /vol1/1.2.2.lyx | |
| parent | 16ccda6c459c0fd7ca2081e9d541124c28b0c556 (diff) | |
Changed layout for more manageable volumes
Diffstat (limited to 'vol1/1.2.2.lyx')
| -rw-r--r-- | vol1/1.2.2.lyx | 1329 |
1 files changed, 1329 insertions, 0 deletions
diff --git a/vol1/1.2.2.lyx b/vol1/1.2.2.lyx new file mode 100644 index 0000000..e964905 --- /dev/null +++ b/vol1/1.2.2.lyx @@ -0,0 +1,1329 @@ +#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 book +\begin_preamble +\input defs +\end_preamble +\use_default_options true +\maintain_unincluded_children no +\language english +\language_package default +\inputencoding utf8 +\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 +\float_placement class +\float_alignment class +\paperfontsize default +\spacing single +\use_hyperref false +\papersize default +\use_geometry false +\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 true +\use_refstyle 1 +\use_formatted_ref 0 +\use_minted 0 +\use_lineno 0 +\index Index +\shortcut idx +\color #008000 +\end_index +\secnumdepth 3 +\tocdepth 3 +\paragraph_separation indent +\paragraph_indentation default +\is_math_indent 0 +\math_numbering_side default +\quotes_style english +\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 Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +exerc1[00] +\end_layout + +\end_inset + +What is the smallest positive rational number? +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + +There isn't. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +exerc2[00] +\end_layout + +\end_inset + +Is +\begin_inset Formula $1+0.239999999\dots$ +\end_inset + + a decimal expansion? +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + +Yes, + as long as it means a number +\begin_inset Formula $x$ +\end_inset + + with +\begin_inset Formula $1.239999999\leq x<1.24$ +\end_inset + +, + that is, + as long as it doesn't end with an infinite number of nines. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +exerc3[02] +\end_layout + +\end_inset + +What is +\begin_inset Formula $(-3)^{-3}$ +\end_inset + +? +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + + +\begin_inset Formula $(-3)^{-3}=\frac{1}{(-3)^{3}}=\frac{1}{-27}=-\frac{1}{27}$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +rexerc4[05] +\end_layout + +\end_inset + +What is +\begin_inset Formula $(0.125)^{-2/3}$ +\end_inset + +? +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + + +\begin_inset Formula $(0.125)^{-2/3}=(\frac{1}{8})^{-2/3}=\sqrt[3]{(\frac{1}{8})^{-2}}=\sqrt[3]{8^{2}}=\sqrt[3]{64}=4$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +exerc5[05] +\end_layout + +\end_inset + +We defined real numbers in terms of a decimal expansion. + Discuss how we could have defined them in terms of a binary expansion instead, + and give a definition to replace Eq. + (2). +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + +A decimal expansion would have the form +\begin_inset Formula $x=n+0.b_{1}b_{2}b_{3}\dots$ +\end_inset + +, + where each +\begin_inset Formula $b_{i}$ +\end_inset + + would be a binary digit, + 0 or 1, + and this would mean that +\begin_inset Formula +\[ +n+\frac{b_{1}}{2}+\frac{b_{2}}{4}+\dots+\frac{b_{k}}{2^{k}}\leq x<n+\frac{b_{1}}{2}+\frac{b_{2}}{4}+\dots+\frac{b_{k}}{2^{k}}+\frac{1}{10^{k}}. +\] + +\end_inset + + +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +exerc6[10] +\end_layout + +\end_inset + +Let +\begin_inset Formula $x=m+0.d_{1}d_{2}\dots$ +\end_inset + + and +\begin_inset Formula $y=n+0.e_{1}e_{2}\dots$ +\end_inset + + be real numbers, + Give a rule for determining whether +\begin_inset Formula $x=y$ +\end_inset + +, + +\begin_inset Formula $x<y$ +\end_inset + +, + or +\begin_inset Formula $x>y$ +\end_inset + +, + based on the decimal representation. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + +We say that +\begin_inset Formula $x=y$ +\end_inset + + if +\begin_inset Formula $m=n$ +\end_inset + + and +\begin_inset Formula $d_{k}=e_{k}$ +\end_inset + + for all +\begin_inset Formula $k$ +\end_inset + +, + and that +\begin_inset Formula $x<y$ +\end_inset + + if +\begin_inset Formula $m<n$ +\end_inset + + or if +\begin_inset Formula $m=n$ +\end_inset + + and there's a +\begin_inset Formula $k$ +\end_inset + + such that +\begin_inset Formula $d_{j}=e_{j}$ +\end_inset + + for +\begin_inset Formula $1\leq j<k$ +\end_inset + + and +\begin_inset Formula $d_{k}<e_{k}$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +rexerc11[10] +\end_layout + +\end_inset + +If +\begin_inset Formula $b=10$ +\end_inset + + and +\begin_inset Formula $x\approx\log_{10}2$ +\end_inset + +, + to how many decimal places of accuracy will we need to know the value of +\begin_inset Formula $x$ +\end_inset + + in order to determine the first three decimal places of the decimal expansion of +\begin_inset Formula $b^{x}$ +\end_inset + +? +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + +Potentially infinite. + Because +\begin_inset Formula $10^{\log_{10}2}=2$ +\end_inset + +, + +\begin_inset Formula $10^{x}=2.0\dots$ +\end_inset + + if +\begin_inset Formula $x\geq\log_{10}2$ +\end_inset + + or +\begin_inset Formula $10^{x}=1.9\dots$ +\end_inset + + if +\begin_inset Formula $x\leq\log_{10}2$ +\end_inset + +, + but since +\begin_inset Formula $\log_{10}2$ +\end_inset + + is irrational, + its decimal expansion is infinite and, + in the worst case that +\begin_inset Formula $x=\log_{10}2$ +\end_inset + +, + we can't determine by an algorithm that +\begin_inset Formula $x\geq\log_{10}2$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +exerc12[02] +\end_layout + +\end_inset + +Explain why Eq. + (10) follows from Eqs. + (8). +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + +Because logarithms are strictly increasing, + continuous functions, + and we have that +\begin_inset Formula $10^{0.30102999}<2<10^{0.30103000}$ +\end_inset + +, + we can take logarithms on the expression to get +\begin_inset Formula $0.30102999<\log_{10}2<0.30103000$ +\end_inset + +, + and so +\begin_inset Formula $\log_{10}2=0.30102999$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +rexerc13[M23] +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Enumerate +Given that +\begin_inset Formula $x$ +\end_inset + + is a positive real number and +\begin_inset Formula $n$ +\end_inset + + is a positive integer, + prove the inequality +\begin_inset Formula $\sqrt[n]{1+x}-1\leq x/n$ +\end_inset + +. +\end_layout + +\begin_layout Enumerate +Use this fact to justify the remarks following (7). +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Enumerate +Let +\begin_inset Formula $f(x):=\sqrt[n]{1+x}-1-\frac{x}{n}$ +\end_inset + +, + we have to prove that, + if +\begin_inset Formula $n$ +\end_inset + + is a positive integer and +\begin_inset Formula $x>0$ +\end_inset + +, + then +\begin_inset Formula $f(x)\leq0$ +\end_inset + +. + We have +\begin_inset Formula +\[ +f'(x)=\frac{1}{n\sqrt[n]{1+x}}-\frac{1}{n}=\frac{1}{n}\left(\frac{1}{\sqrt[n]{1+x}-1}\right), +\] + +\end_inset + +but since +\begin_inset Formula $\sqrt[n]{1+x}>1$ +\end_inset + + for +\begin_inset Formula $x>0$ +\end_inset + +, + we have +\begin_inset Formula $f'(x)<0$ +\end_inset + + and +\begin_inset Formula $f$ +\end_inset + + is strictly decreasing on +\begin_inset Formula $(0,+\infty)$ +\end_inset + +. + Since +\begin_inset Formula $f(0)=0$ +\end_inset + +, + this proves the result. +\end_layout + +\begin_layout Enumerate +It's clear that +\begin_inset Formula $b^{n+d_{1}/10+\dots+d_{k}/10^{k}}\leq b^{n+1}$ +\end_inset + +, + and then, + taken +\begin_inset Formula $x=b-1>0$ +\end_inset + + and +\begin_inset Formula $n=10^{k}$ +\end_inset + +, + we have +\begin_inset Formula $\sqrt[10^{k}]{1+b-1}=b^{1/10^{k}}\leq(b-1)/10^{k}$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +exerc15[10] +\end_layout + +\end_inset + +Prove or disprove: +\begin_inset Formula +\begin{align*} +\log_{b}x/y & =\log_{b}x-\log_{b}y, & \text{if }x,y & >0. +\end{align*} + +\end_inset + + +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + +Let +\begin_inset Formula $\alpha:=\log_{b}x$ +\end_inset + + and +\begin_inset Formula $\beta:=\log_{b}y$ +\end_inset + +, + we have +\begin_inset Formula +\[ +\frac{b^{\alpha}}{b^{\beta}}=b^{\alpha}b^{-\beta}=b^{\alpha-\beta}, +\] + +\end_inset + +and taking logarithms, + we get +\begin_inset Formula $\log_{b}\frac{b^{\alpha}}{b^{\beta}}=\log_{b}\frac{x}{y}=\log_{b}b^{\alpha-\beta}=\alpha-\beta=\log_{b}x-\log_{b}y.$ +\end_inset + + +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +exerc16[00] +\end_layout + +\end_inset + +How can +\begin_inset Formula $\log_{10}x$ +\end_inset + + be expressed in terms of +\begin_inset Formula $\ln x$ +\end_inset + + and +\begin_inset Formula $\ln10$ +\end_inset + +? +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + + +\begin_inset Formula $\log_{10}x=\frac{\log_{e}x}{\log_{e}10}=\frac{\ln x}{\ln10}$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +rexerc17[05] +\end_layout + +\end_inset + +What is +\begin_inset Formula $\lg32$ +\end_inset + +? + +\begin_inset Formula $\log_{\pi}\pi$ +\end_inset + +? + +\begin_inset Formula $\ln e$ +\end_inset + +? + +\begin_inset Formula $\log_{b}1$ +\end_inset + +? + +\begin_inset Formula $\log_{b}(-1)$ +\end_inset + +? +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + + +\begin_inset Formula $\lg32=5$ +\end_inset + +, + +\begin_inset Formula $\log_{\pi}\pi=1$ +\end_inset + +, + +\begin_inset Formula $\ln e=1$ +\end_inset + +, + +\begin_inset Formula $\log_{b}1=0$ +\end_inset + +. + As for +\begin_inset Formula $\log_{b}(-1)$ +\end_inset + +, + it would be an +\begin_inset Formula $x$ +\end_inset + + such that +\begin_inset Formula $b^{x}=-1$ +\end_inset + +, + which is not a real number most of the time. + As a complex number, + it would be +\begin_inset Formula $\log_{b}(-1)=\frac{\ln(-1)}{\ln b}=\frac{i\pi}{\ln b}$ +\end_inset + +, + since +\begin_inset Formula $e^{i\pi}=-1$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +exerc18[10] +\end_layout + +\end_inset + +Prove or disprove: + +\begin_inset Formula $\log_{8}x=\frac{1}{2}\lg x$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + + +\begin_inset Formula $\log_{8}x=\frac{\lg x}{\lg8}$ +\end_inset + +, + but +\begin_inset Formula $\lg8=3\neq2$ +\end_inset + +, + so this is false in the general case (this is only true when +\begin_inset Formula $x=1$ +\end_inset + +). +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +rexerc19[20] +\end_layout + +\end_inset + +If +\begin_inset Formula $n$ +\end_inset + + is an integer whose decimal representation is 14 digits long, + will the value of +\begin_inset Formula $n$ +\end_inset + + fit in a computer word with a capacity of 47 bits and a sign bit? +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + +The number of possibilities for a number with up to 14 digits is +\begin_inset Formula $10^{14}$ +\end_inset + +, + and the number for 47 bits is +\begin_inset Formula $2^{47}\approx1.3\cdot2^{14}$ +\end_inset + +, + so it would fit. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +exerc20[10] +\end_layout + +\end_inset + +Is there any simple relation between +\begin_inset Formula $\log_{10}2$ +\end_inset + + and +\begin_inset Formula $\log_{2}10$ +\end_inset + +? +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + + +\begin_inset Formula $\log_{10}2=\frac{\log_{2}2}{\log_{2}10}=\frac{1}{\log_{2}10}$ +\end_inset + +, + so +\begin_inset Formula $\log_{10}2\log_{2}10=1$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +rexerc22[20] +\end_layout + +\end_inset + +(R. + W. + Hamming.) Prove that +\begin_inset Formula +\[ +\lg x\approx\ln x+\log_{10}x, +\] + +\end_inset + +with less than +\begin_inset Formula $\unit[1]{\%}$ +\end_inset + + error! + (Thus a table of natural logarithms and of common logarithms can be used to get approximate values of binary logarithms as well.) +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + + +\begin_inset Formula +\[ +\ln x+\log_{10}x=\frac{\lg x}{\lg e}+\frac{\lg x}{\lg10}=\lg x\left(\frac{1}{\lg e}+\frac{1}{\lg10}\right)\cong0.994\lg x\approx\lg x, +\] + +\end_inset + +and this gives us about +\begin_inset Formula $\unit[0.6]{\%}$ +\end_inset + + error. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +rexerc27[M25] +\end_layout + +\end_inset + +Consider the method for calculating +\begin_inset Formula $\log_{10}x$ +\end_inset + + discussed in the text. + Let +\begin_inset Formula $x'_{k}$ +\end_inset + + denote the computed approximation to +\begin_inset Formula $x_{k}$ +\end_inset + +, + determined as follows: + +\begin_inset Formula $x(1-\delta)\leq10^{n}x'_{0}\leq x(1+\epsilon)$ +\end_inset + +; + and in the determination of +\begin_inset Formula $x'_{k}$ +\end_inset + + by Eqs. + (18), + the quantity +\begin_inset Formula $y_{k}$ +\end_inset + + is used in place of +\begin_inset Formula $(x'_{k-1})^{2}$ +\end_inset + +, + where +\begin_inset Formula $(x'_{k-1})^{2}(1-\delta)\leq y_{k}\leq(x'_{k-1})^{2}(1+\epsilon)$ +\end_inset + + and +\begin_inset Formula $1\leq y_{k}<100$ +\end_inset + +. + Here +\begin_inset Formula $\delta$ +\end_inset + + and +\begin_inset Formula $\epsilon$ +\end_inset + + are small constants that reflect the upper and lower errors due to rounding or truncation. + If +\begin_inset Formula $\log^{\prime}x$ +\end_inset + + denotes the result of the calculations, + show that after +\begin_inset Formula $k$ +\end_inset + + steps we have +\begin_inset Formula +\[ +\log_{10}x+2\log_{10}(1-\delta)-1/2^{k}<\log^{\prime}x\leq\log_{10}x+2\log_{10}(1+\epsilon). +\] + +\end_inset + + +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +answer +\end_layout + +\end_inset + +We first prove by induction that +\begin_inset Formula +\[ +x^{2^{k}}(1-\delta)^{2^{k+1}-1}\leq10^{2^{k}(n+b_{1}/2+\dots+b_{k}/2^{k})}x'_{k}\leq x^{2^{k}}(1+\epsilon)^{2^{k+1}-1}. +\] + +\end_inset + +For +\begin_inset Formula $k=0$ +\end_inset + +, + we have +\begin_inset Formula $x(1-\delta)\leq10^{n}x'_{0}\leq x(1+\epsilon)$ +\end_inset + +, + which is given. + If this holds up to a certain +\begin_inset Formula $k$ +\end_inset + +, + then if +\begin_inset Formula $(x'_{k})^{2}<10$ +\end_inset + +, + we have +\begin_inset Formula $b_{k+1}=0$ +\end_inset + +, + +\begin_inset Formula $(1-\delta)(x'_{k})^{2}\leq x'_{k+1}\leq(1+\epsilon)(x'_{k})^{2}$ +\end_inset + + and +\begin_inset Formula +\begin{eqnarray*} +x^{2^{k+1}}(1-\delta)^{2^{k+2}-1} & = & (x^{2^{k+1}}(1-\delta)^{2^{k+1}-1})^{2}(1-\delta)\\ + & \leq & (10^{2^{k}(n+b_{1}/2+\dots+b_{k}/2^{k})}x'_{k})^{2}(1-\delta)\\ + & \leq & 10^{2^{k+1}(n+b_{1}/2+\dots+b_{k}/2^{k}+b_{k+1}/2^{k+1})}x'_{k+1}\\ + & \leq & (10^{2^{k}(n+b_{1}/2+\dots+b_{k}/2^{k})}x'_{k})^{2}(1+\epsilon)\\ + & \leq & (x^{2^{k}}(1+\epsilon)^{2^{k+1}-1})^{2}(1+\epsilon)=x^{2^{k+1}}(1+\epsilon)^{2^{k+2}-1}. +\end{eqnarray*} + +\end_inset + +If +\begin_inset Formula $(x'_{k})^{2}\geq10$ +\end_inset + +, + we have +\begin_inset Formula $b_{k+1}=1$ +\end_inset + +, + +\begin_inset Formula $(1-\delta)(x'_{k})^{2}\leq10x'_{k+1}\leq(1+\epsilon)(x'_{k})^{2}$ +\end_inset + + and +\begin_inset Formula +\begin{eqnarray*} +x^{2^{k+1}}(1-\delta)^{2^{k+2}-1} & \leq & (10^{2^{k}(n+b_{1}/2+\dots+b_{k}/2^{k})}x'_{k})^{2}(1-\delta)\\ + & \leq & 10^{2^{k+1}(n+b_{1}/2+\dots+b_{k}/2^{k})}10x'_{k+1}\\ + & = & 10^{2^{k+1}(n+b_{1}/2+\dots+b_{k}/2^{k}+b_{k+1}/2^{k+1})}x'_{k+1}\\ + & \leq & (10^{2^{k}(n+b_{1}/2+\dots+b_{k}/2^{k})}x'_{k})^{2}(1+\epsilon)\\ + & \leq & x^{2^{k+1}}(1+\epsilon)^{2^{k+2}-1}. +\end{eqnarray*} + +\end_inset + +Then, + by taking logarithms on the expression, + we get +\begin_inset Formula +\[ +2^{k}\log x+(2^{k+1}-1)\log(1-\delta)\leq2^{k}\log^{\prime}x+\log x'_{k}\leq2^{k}\log x+(2^{k+1}-1)\log(1+\epsilon). +\] + +\end_inset + +Finally, + subtracting +\begin_inset Formula $\log x'_{k}$ +\end_inset + + from all sides, + using that +\begin_inset Formula $-1<-\log(1-\delta)-\log x'_{k}=-\log(x'_{k}(1-\delta))$ +\end_inset + +, + because +\begin_inset Formula $x'_{k}(1-\delta)<10$ +\end_inset + +, + using that +\begin_inset Formula $-\log(1+\epsilon)-\log x'_{k}=-\log(x'_{k}(1+\epsilon))\leq0$ +\end_inset + +, + because +\begin_inset Formula $x'_{k}(1+\epsilon)\geq1$ +\end_inset + +, + and dividing everything by +\begin_inset Formula $2^{k}$ +\end_inset + +, + we get +\begin_inset Formula +\[ +\log x+2\log(1-\delta)-\frac{1}{2^{k}}<\log^{\prime}x\leq\log x+2\log(1+\epsilon), +\] + +\end_inset + +which is precisely what we wanted to prove. +\end_layout + +\end_body +\end_document |
