\documentclass[10pt,a4paper]{article} % Packages \usepackage{fancyhdr} % For header and footer \usepackage{multicol} % Allows multicols in tables \usepackage{tabularx} % Intelligent column widths \usepackage{tabulary} % Used in header and footer \usepackage{hhline} % Border under tables \usepackage{graphicx} % For images \usepackage{xcolor} % For hex colours %\usepackage[utf8x]{inputenc} % For unicode character support \usepackage[T1]{fontenc} % Without this we get weird character replacements \usepackage{colortbl} % For coloured tables \usepackage{setspace} % For line height \usepackage{lastpage} % Needed for total page number \usepackage{seqsplit} % Splits long words. %\usepackage{opensans} % Can't make this work so far. Shame. Would be lovely. \usepackage[normalem]{ulem} % For underlining links % Most of the following are not required for the majority % of cheat sheets but are needed for some symbol support. \usepackage{amsmath} % Symbols \usepackage{MnSymbol} % Symbols \usepackage{wasysym} % Symbols %\usepackage[english,german,french,spanish,italian]{babel} % Languages % Document Info \author{ebabor} \pdfinfo{ /Title (sequences-and-series.pdf) /Creator (Cheatography) /Author (ebabor) /Subject (Sequences and Series Cheat Sheet) } % Lengths and widths \addtolength{\textwidth}{6cm} \addtolength{\textheight}{-1cm} \addtolength{\hoffset}{-3cm} \addtolength{\voffset}{-2cm} \setlength{\tabcolsep}{0.2cm} % Space between columns \setlength{\headsep}{-12pt} % Reduce space between header and content \setlength{\headheight}{85pt} % If less, LaTeX automatically increases it \renewcommand{\footrulewidth}{0pt} % Remove footer line \renewcommand{\headrulewidth}{0pt} % Remove header line \renewcommand{\seqinsert}{\ifmmode\allowbreak\else\-\fi} % Hyphens in seqsplit % This two commands together give roughly % the right line height in the tables \renewcommand{\arraystretch}{1.3} \onehalfspacing % Commands \newcommand{\SetRowColor}[1]{\noalign{\gdef\RowColorName{#1}}\rowcolor{\RowColorName}} % Shortcut for row colour \newcommand{\mymulticolumn}[3]{\multicolumn{#1}{>{\columncolor{\RowColorName}}#2}{#3}} % For coloured multi-cols \newcolumntype{x}[1]{>{\raggedright}p{#1}} % New column types for ragged-right paragraph columns \newcommand{\tn}{\tabularnewline} % Required as custom column type in use % Font and Colours \definecolor{HeadBackground}{HTML}{333333} \definecolor{FootBackground}{HTML}{666666} \definecolor{TextColor}{HTML}{333333} \definecolor{DarkBackground}{HTML}{A39C3B} \definecolor{LightBackground}{HTML}{F9F8F2} \renewcommand{\familydefault}{\sfdefault} \color{TextColor} % Header and Footer \pagestyle{fancy} \fancyhead{} % Set header to blank \fancyfoot{} % Set footer to blank \fancyhead[L]{ \noindent \begin{multicols}{3} \begin{tabulary}{5.8cm}{C} \SetRowColor{DarkBackground} \vspace{-7pt} {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}} } \end{tabulary} \columnbreak \begin{tabulary}{11cm}{L} \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Sequences and Series Cheat Sheet}}}} \\ \normalsize{by \textcolor{DarkBackground}{ebabor} via \textcolor{DarkBackground}{\uline{cheatography.com/69500/cs/17544/}}} \end{tabulary} \end{multicols}} \fancyfoot[L]{ \footnotesize \noindent \begin{multicols}{3} \begin{tabulary}{5.8cm}{LL} \SetRowColor{FootBackground} \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}} \\ \vspace{-2pt}ebabor \\ \uline{cheatography.com/ebabor} \\ \end{tabulary} \vfill \columnbreak \begin{tabulary}{5.8cm}{L} \SetRowColor{FootBackground} \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}} \\ \vspace{-2pt}Published 22nd October, 2018.\\ Updated 22nd October, 2018.\\ Page {\thepage} of \pageref{LastPage}. \end{tabulary} \vfill \columnbreak \begin{tabulary}{5.8cm}{L} \SetRowColor{FootBackground} \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Sponsor}} \\ \SetRowColor{white} \vspace{-5pt} %\includegraphics[width=48px,height=48px]{dave.jpeg} Measure your website readability!\\ www.readability-score.com \end{tabulary} \end{multicols}} \begin{document} \raggedright \raggedcolumns % Set font size to small. Switch to any value % from this page to resize cheat sheet text: % www.emerson.emory.edu/services/latex/latex_169.html \footnotesize % Small font. \begin{multicols*}{3} \begin{tabularx}{5.377cm}{X} \SetRowColor{DarkBackground} \mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{General Rules}} \tn % Row 0 \SetRowColor{LightBackground} \mymulticolumn{1}{x{5.377cm}}{Telescoping and Geometric series are the only types of series that you can estimate sums from. So, you must use these test's properties to estimate these sums} \tn % Row Count 4 (+ 4) % Row 1 \SetRowColor{white} \mymulticolumn{1}{x{5.377cm}}{If the question is asking for absolute convergence or conditional convergence. You will need to use the Ratio Test, Root Test, or the definition of Absolute/Conditional Convergence} \tn % Row Count 8 (+ 4) % Row 2 \SetRowColor{LightBackground} \mymulticolumn{1}{x{5.377cm}}{Must show {\bf{ALL}} work to receive full credit for questions. Study the process to solve the problems, don't just guess through the review} \tn % Row Count 11 (+ 3) \hhline{>{\arrayrulecolor{DarkBackground}}-} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{1.32733 cm} x{1.41887 cm} x{1.8308 cm} } \SetRowColor{DarkBackground} \mymulticolumn{3}{x{5.377cm}}{\bf\textcolor{white}{Tests}} \tn % Row 0 \SetRowColor{LightBackground} Test for \seqsplit{Divergence(TFD)} & \seqsplit{Inconclusive} & You absolutely cannot determine if a series is convergent from this test. \tn % Row Count 5 (+ 5) % Row 1 \SetRowColor{white} & Diverges & If limit of series ≠0 or ∞ \tn % Row Count 7 (+ 2) % Row 2 \SetRowColor{LightBackground} Integral Test & Converges & If integral of series \textless{}∞ \tn % Row Count 9 (+ 2) % Row 3 \SetRowColor{white} & Diverges & If integral of series =∞ \tn % Row Count 11 (+ 2) % Row 4 \SetRowColor{LightBackground} Ratio Test & \seqsplit{Converges/Converges} Absolutely & If limit of 0≤|(a`k+1`) /(a`k`)|\textless{}1 \tn % Row Count 14 (+ 3) % Row 5 \SetRowColor{white} & Diverges & If limit \textgreater{}1 \tn % Row Count 15 (+ 1) % Row 6 \SetRowColor{LightBackground} & \seqsplit{Inconclusive} & If limit =1 \tn % Row Count 16 (+ 1) % Row 7 \SetRowColor{white} Root Test & \seqsplit{Converges/Converges} Absolutely & If 0≤limit of the k\textasciicircum{}th\textasciicircum{} root of |a`k`|\textless{}1 \tn % Row Count 19 (+ 3) % Row 8 \SetRowColor{LightBackground} & Diverges & If limit of the k\textasciicircum{}th\textasciicircum{} root of |a`k`|\textgreater{}1 \tn % Row Count 22 (+ 3) % Row 9 \SetRowColor{white} & \seqsplit{Inconclusive} & If limit of k\textasciicircum{}th\textasciicircum{} root of |a`k`|=1 \tn % Row Count 25 (+ 3) % Row 10 \SetRowColor{LightBackground} Direct Comparison Test(CT) & Converges & If ∑b`k` converges AND b`k` is the larger of the two functions \tn % Row Count 29 (+ 4) % Row 11 \SetRowColor{white} & Diverges & If ∑b`k` diverges AND b`k` is smaller of two functions \tn % Row Count 33 (+ 4) \end{tabularx} \par\addvspace{1.3em} \vfill \columnbreak \begin{tabularx}{5.377cm}{x{1.32733 cm} x{1.41887 cm} x{1.8308 cm} } \SetRowColor{DarkBackground} \mymulticolumn{3}{x{5.377cm}}{\bf\textcolor{white}{Tests (cont)}} \tn % Row 12 \SetRowColor{LightBackground} Limit Comparison Test(LCT) & Converges & If b`k` converges AND limit of 0\textless{}(a`k`)/(b`k`)\textless{}∞ \tn % Row Count 4 (+ 4) % Row 13 \SetRowColor{white} & Diverges & If b`k` AND limit of 0\textless{}(a`k`)/(b`k`)\textless{}∞ \tn % Row Count 7 (+ 3) % Row 14 \SetRowColor{LightBackground} \seqsplit{Alternating} Series Test(AST) & Converges & If all 3 conditions for AST are met \tn % Row Count 10 (+ 3) % Row 15 \SetRowColor{white} & Diverges & If limit condition fails, ∑a`k` is immediately divergent by TFD \tn % Row Count 15 (+ 5) \hhline{>{\arrayrulecolor{DarkBackground}}---} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{1.28156 cm} x{1.19002 cm} x{2.10542 cm} } \SetRowColor{DarkBackground} \mymulticolumn{3}{x{5.377cm}}{\bf\textcolor{white}{Properties of Special Series}} \tn % Row 0 \SetRowColor{LightBackground} Geometric Series & Converges & If Absolute Value of r\textless{}1. Converges at S=(first term)/(1-r) \tn % Row Count 4 (+ 4) % Row 1 \SetRowColor{white} & Diverges & If Absolute Value of r≥1 \tn % Row Count 6 (+ 2) % Row 2 \SetRowColor{LightBackground} P-Series & Converges & If p\textgreater{}1 \tn % Row Count 7 (+ 1) % Row 3 \SetRowColor{white} & Diverges & If p≤1 \tn % Row Count 8 (+ 1) % Row 4 \SetRowColor{LightBackground} \seqsplit{Telescoping} & Converges & Value that the limit of the remaining terms approach \tn % Row Count 11 (+ 3) % Row 5 \SetRowColor{white} & Diverges & Almost never. On the test it will converge \tn % Row Count 14 (+ 3) % Row 6 \SetRowColor{LightBackground} Definition of \seqsplit{Convergence} & Absolute \seqsplit{Convergence} & If and only if ∑|a`k`| is convergent \tn % Row Count 17 (+ 3) % Row 7 \SetRowColor{white} & \seqsplit{Conditional} \seqsplit{Convergence} & If and only if ∑a`k` is convergent, but ∑|a`k`| is divergent \tn % Row Count 21 (+ 4) \hhline{>{\arrayrulecolor{DarkBackground}}---} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{2.04057 cm} x{2.93643 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{When to Use Tests}} \tn % Row 0 \SetRowColor{LightBackground} Properties & If you can identify the series as a geometric, p, or telescoping series, then use their respective properties. If the given series looks {\emph{close}} to one of these series {\bf{see if you can use algebra to rearrange it into one of them}} \tn % Row Count 11 (+ 11) % Row 1 \SetRowColor{white} Test for Divergence(TFD) & Should at least eyeball this test first to see if the limit of the series does not approach 0. If series does not approach 0, then {\bf{∑a`k` divergent by TFD}} \tn % Row Count 18 (+ 7) % Row 2 \SetRowColor{LightBackground} Comparison Tests(CT and LCT) & {\bf{ONLY POSITIVE TERMS!}} If you can tell if the series has negative terms,((-1)\textasciicircum{}k\textasciicircum{} or sin/cos), do not use this test. If series has is rational and has a root in the denominator, compare with a p-series. |a`k`| gives use absolute convergence \tn % Row Count 29 (+ 11) % Row 3 \SetRowColor{white} Alternating Series Test(AST) & Series with (-1)\textasciicircum{}k\textasciicircum{} can be testes with AST \tn % Row Count 31 (+ 2) \end{tabularx} \par\addvspace{1.3em} \vfill \columnbreak \begin{tabularx}{5.377cm}{x{2.04057 cm} x{2.93643 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{When to Use Tests (cont)}} \tn % Row 4 \SetRowColor{LightBackground} Integral Test & {\bf{ONLY POSITIVE TERMS!}} If you can look at the function and easily take the integral, it is probably good to use this test \tn % Row Count 6 (+ 6) % Row 5 \SetRowColor{white} Ratio Test & If series contains: k!, or powers {\emph{and}} exponentials, {\bf{almost guaranteed to use ratio test}} \tn % Row Count 11 (+ 5) % Row 6 \SetRowColor{LightBackground} Root Test & If the entire series can be written to the k\textasciicircum{}th\textasciicircum{} power, you can use the root test \tn % Row Count 15 (+ 4) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{X} \SetRowColor{DarkBackground} \mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Integral Test}} \tn \SetRowColor{white} \mymulticolumn{1}{x{5.377cm}}{Conditions: \newline % Row Count 1 (+ 1) 1. f(x) is positive on its interval \newline % Row Count 2 (+ 1) 2. f(x) is continuous on its interval \newline % Row Count 3 (+ 1) 3. f(x) decreasing as x-\textgreater{}∞ (derivative is negative) \newline % Row Count 5 (+ 2) * Must change a`k` to a function in order to take derivative \newline % Row Count 7 (+ 2) * Integral starts off from k to ∞, so you must change the integral to k to t with limit as t-\textgreater{}∞ \newline % Row Count 10 (+ 3) * Answer you get is not where the ∑a`k` converges% Row Count 12 (+ 2) } \tn \hhline{>{\arrayrulecolor{DarkBackground}}-} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{X} \SetRowColor{DarkBackground} \mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Alternating Series Test}} \tn \SetRowColor{white} \mymulticolumn{1}{x{5.377cm}}{Conditions: \newline % Row Count 1 (+ 1) 1. b`k`\textgreater{}0 \newline % Row Count 2 (+ 1) 2. b`k`≥b`k+1` \newline % Row Count 3 (+ 1) 3. limit of b`k`=0 \newline % Row Count 4 (+ 1) * If ∑b`k` fits all three conditions, ∑a`k` convergent by AST \newline % Row Count 6 (+ 2) * If 3\textasciicircum{}rd\textasciicircum{} condition fails, ∑a`k` is divergent by TFD \newline % Row Count 8 (+ 2) * If series contains (-m)\textasciicircum{}k\textasciicircum{}, pull (-1)\textasciicircum{}k\textasciicircum{} out and keep m\textasciicircum{}k\textasciicircum{} in b`k`% Row Count 10 (+ 2) } \tn \hhline{>{\arrayrulecolor{DarkBackground}}-} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{0.9154 cm} x{2.15119 cm} x{1.51041 cm} } \SetRowColor{DarkBackground} \mymulticolumn{3}{x{5.377cm}}{\bf\textcolor{white}{Integral Remainder}} \tn % Row 0 \SetRowColor{LightBackground} Known n\textasciicircum{}th\textasciicircum{} Value & Solving for S`n`(sum of the series approximation) & Plug n into the series \tn % Row Count 3 (+ 3) % Row 1 \SetRowColor{white} & Solving for R`n` (approximation of the remainder) & Solve integral from n to ∞ \tn % Row Count 6 (+ 3) % Row 2 \SetRowColor{LightBackground} Known Error Bound & Set the integral of f(x) from n to ∞ less than error bound. Once solved, answer will be given in terms of n\textless{}\#. Must round up the number since series only use integers and if you rounded down, the value of the integral would be larger than the error bound & \tn % Row Count 21 (+ 15) \hhline{>{\arrayrulecolor{DarkBackground}}---} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{5.377cm}{x{1.05271 cm} x{2.47158 cm} x{1.05271 cm} } \SetRowColor{DarkBackground} \mymulticolumn{3}{x{5.377cm}}{\bf\textcolor{white}{Alternating Series Remainder}} \tn % Row 0 \SetRowColor{LightBackground} Known Error Bound & Set error bound less than b`n+1`. Solve for a \#\textgreater{}n, round up n to next highest whole number & \tn % Row Count 5 (+ 5) % Row 1 \SetRowColor{white} & If the inequality is very difficult to solve, the use of a table, shown below, is acceptable. When the middle column, b`n+1`, is less than third column, error bound, then that value is you final answer for n. Since the original variable in the equation is k, and k=n+1, then the value of the final term you can stop on to reach your error bound will be k & \tn % Row Count 22 (+ 17) % Row 2 \SetRowColor{LightBackground} \mymulticolumn{3}{x{5.377cm}}{} \tn % Row Count 22 (+ 0) % Row 3 \SetRowColor{white} n\textasciicircum{}th\textasciicircum{} term\{\{br\}\} & b`n+1`\{\{br\}\} & Error Bound\{\{br\}\} \tn % Row Count 24 (+ 2) \hhline{>{\arrayrulecolor{DarkBackground}}---} \end{tabularx} \par\addvspace{1.3em} % That's all folks \end{multicols*} \end{document}