#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 \use_default_options true \maintain_unincluded_children no \language american \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 true \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 Note Note status open \begin_layout Plain Layout TODO 4, 6 (1 p.) (est. 0:13:30) \end_layout \end_inset \end_layout \begin_layout Standard \begin_inset ERT status open \begin_layout Plain Layout \backslash rexerc4[HM10] \end_layout \end_inset Prove Eq. (13). \end_layout \begin_layout Standard \begin_inset ERT status open \begin_layout Plain Layout \backslash answer \end_layout \end_inset Since \begin_inset Formula $u\geq0$ \end_inset , \begin_inset Formula $\ln(1+u)\geq0$ \end_inset and \begin_inset Formula $u=v+\ln(1+u)\geq v$ \end_inset . On the other hand, \begin_inset Formula $x$ \end_inset is fixed with respect to \begin_inset Formula $v$ \end_inset , so by monotonicity of the integral, if \begin_inset Formula $v\geq1$ \end_inset , \begin_inset Formula \begin{multline*} 0\leq\int_{r}^{\infty}x\text{e}^{-xv}\left(1+\frac{1}{u}\right)\text{d}v\leq\int_{r}^{\infty}x\text{e}^{-xv}\left(1+\frac{1}{v}\right)\text{d}v\leq\int_{r}^{\infty}2x\text{e}^{-xv}=\\ =\left.-2\text{e}^{-xv}\right|_{v=r}^{\infty}=2\text{e}^{-rx}. \end{multline*} \end_inset This means \begin_inset Formula $\int_{r}^{\infty}x\text{e}^{-xv}\left(1+\frac{1}{u}\right)\text{d}v=O(\text{e}^{-rx})$ \end_inset . \end_layout \begin_layout Standard \begin_inset ERT status open \begin_layout Plain Layout \backslash rexerc6[HM20] \end_layout \end_inset Prove Eq. (23). \end_layout \begin_layout Standard \begin_inset ERT status open \begin_layout Plain Layout \backslash answer \end_layout \end_inset \begin_inset Formula \[ (n+\alpha)^{n+\beta}=n^{n+\beta}\left(1+\frac{\alpha}{n}\right)^{n+\beta}. \] \end_inset For the second factor, \begin_inset Formula \begin{multline*} \ln\left(1+\frac{\alpha}{n}\right)^{n+\beta}=(n+\beta)\ln\left(1+\frac{\alpha}{n}\right)=(n+\beta)\left(\frac{\alpha}{n}-\frac{\alpha^{2}}{2n^{2}}+O(n^{-3})\right)=\\ =\alpha+\frac{1}{n}\left(\alpha\beta-\frac{\alpha^{2}}{2}\right)+O(n^{-2}), \end{multline*} \end_inset so \begin_inset Formula \begin{multline*} n^{n+\beta}\left(1+\frac{\alpha}{n}\right)^{n+\beta}=n^{n+\beta}\text{e}^{\alpha}\exp\left(\frac{1}{n}\left(\alpha\beta-\frac{\alpha^{2}}{2}\right)+O(n^{-2})\right)=\\ n^{n+\beta}\text{e}^{\alpha}\left(1+\frac{\alpha}{n}\left(\beta-\frac{\alpha}{2}\right)+O(n^{-2})\right). \end{multline*} \end_inset \end_layout \end_body \end_document