% Required to support mathematical unicode \usepackage[warnunknown, fasterrors, mathletters]{ucs} \usepackage[utf8x]{inputenc} % Always typeset math in display style \everymath{\displaystyle} % Use a larger font size \usepackage[fontsize=14pt]{scrextend} % Standard mathematical typesetting packages \usepackage{amsfonts, amsthm, amsmath, amssymb} \usepackage{mathtools} % Extension to amsmath % Symbol and utility packages \usepackage{cancel, textcomp} \usepackage[mathscr]{euscript} \usepackage[nointegrals]{wasysym} % Extras \usepackage{physics} % Lots of useful shortcuts and macros \usepackage{tikz-cd} % For drawing commutative diagrams easily \usepackage{color} % Add some colour to life \usepackage{microtype} % Minature font tweaks % Common shortcuts \def\mbb#1{\mathbb{#1}} \def\mfk#1{\mathfrak{#1}} \def\bN{\mbb{N}} \def\bC{\mbb{C}} \def\bR{\mbb{R}} \def\bQ{\mbb{Q}} \def\bZ{\mbb{Z}} % Sometimes helpful macros \newcommand{\func}[3]{#1\colon#2\to#3} \newcommand{\vfunc}[5]{\func{#1}{#2}{#3},\quad#4\longmapsto#5} \newcommand{\floor}[1]{\left\lfloor#1\right\rfloor} \newcommand{\ceil}[1]{\left\lceil#1\right\rceil} % Some standard theorem definitions \newtheorem{Theorem}{Theorem} \newtheorem{Proposition}{Theorem} \newtheorem{Lemma}[Theorem]{Lemma} \newtheorem{Corollary}[Theorem]{Corollary} \theoremstyle{definition} \newtheorem{Definition}[Theorem]{Definition} % COPY AND PASTE BELOW TO USE FOR TEXIT % more Blackboard letters \def\bI{\mbb{I}} \def\bH{\mbb{H}} % brackets & parens stuff \newcommand{\br}[1]{\left(#1\right)} \newcommand{\sbr}[1]{\left[#1\right]} \newcommand{\brc}[1]{\left\{#1\right\}} \newcommand{\lbr}[1]{\left\langle#1\right\rangle} % thanks Tuong for the \fxn cmd \newcommand{\fxn}[5]{#1:\begin{array}{rcl}#2&\longrightarrow & #3\\[-0.5mm]#4&\longmapsto \end{array}} \newcommand{\sm}{\setminus} \newcommand{\lc}{\epsilon_{ijk}} \newcommand{\ep}{\epsilon} \newcommand{\vp}{\varphi} \newcommand{\sto}{\longrightarrow} \newcommand{\cjg}[1]{\overline{#1}} \newcommand{\ph}[2]{#1\angle\br{#2}} \newcommand{\inv}{^{-1}} \renewcommand{\L}{\mathcal{L}} \newcommand{\F}{\mathcal{F}} % more function names \DeclareMathOperator{\arcsinh}{arcsinh} \DeclareMathOperator{\arccosh}{arccosh} \DeclareMathOperator{\arctanh}{arctanh} \DeclareMathOperator{\arccsch}{arccsch} \DeclareMathOperator{\arcsech}{arcsech} \DeclareMathOperator{\arccoth}{arccoth} \DeclareMathOperator{\cis}{cis} \DeclareMathOperator{\sinc}{sinc} \DeclareMathOperator{\sgn}{sgn} \DeclareMathOperator{\rect}{rect} \DeclareMathOperator{\tri}{tri} % linalg stuff \renewcommand{\i}{\hat{\imath}} \renewcommand{\j}{\hat{\jmath}} \renewcommand{\k}{\hat{k}} \renewcommand{\l}{\hat{\ell}} \DeclareMathOperator{\cof}{cof} \DeclareMathOperator{\adj}{adj} \DeclareMathOperator{\Span}{span} \DeclareMathOperator{\diag}{diag} \DeclareMathOperator{\rref}{RREF} \DeclareMathOperator{\REF}{REF} \newcommand{\proj}[2]{\text{proj}_{#2}\br{#1}} \newcommand{\m}[2][p]{\begin{#1matrix}#2\end{#1matrix}} \newcommand{\arr}[3][\br]{#1{\begin{array}{#2}#3\end{array}}} % for fun \newcommand{\lhban}{~\color{red}{\cancel{\color{black}\fontsize{10}{0}\text{LH}}}\hspace{-16.6pt}\fontsize{60}{0}\raisebox{-2.7pt}\Circle} \newcommand{\meow}{\approx\mkern-5mu\mathcal{O}\omega\mathcal{O}\mkern-5mu\approx} \newcommand{\limdefn}{f'(x)=\lim_{h\to0}\tfrac{f(x+h)-f(x)}h} \newcommand{\trig}{\text{A relatively small list of trigonometric identities:}\\\\\text{defining relations:}\\ \csc(x)=\tfrac1{\sin(x)}\quad\tan(x)=\tfrac{\sin(x)}{\cos(x)}\\ \sec(x)=\tfrac1{\cos(x)}\quad\cot(x)=\tfrac1{\tan(x)}=\tfrac{\cos(x)}{\sin(x)}\\\\ \text{pythagoras:}\\ \sin^2(x)+\cos^2(x)=1\\ 1+\cot^2(x)=\csc^2(x)\\ \tan^2(x)+1=\sec^2(x)\\\\ \text{cofunction, negative angle, and supplement:}\\ \sin(x)=\cos(\tfrac\pi2-x)\quad\sin(-x)=-\sin(x)\\ \cos(x)=\sin(\tfrac\pi2-x)\quad\cos(-x)=\cos(x)\\ \tan(x)=\cot(\tfrac\pi2-x)\quad\tan(-x)=-\tan(x)\\ \sin(\pi-x)=\sin(x)\\ \cos(\pi-x)=-\cos(x)\\ \tan(\pi-x)=-\tan(x)\\\\ \text{periodicity - for all }n\in\bZ\text{, we have:}\\ \sin(x+2\pi n)=\sin(x)\\ \cos(x+2\pi n)=\cos(x)\\ \tan(x+\pi n)=\tan(x)\\\\ \text{addition:}\\ \sin(x\pm y)=\sin(x)\cos(y)\pm\cos(x)\sin(y)\\ \cos(x\pm y)=\cos(x)\cos(y)\mp\sin(x)\sin(y)\\ \tan(x\pm y)=\tfrac{\tan(x)\pm\tan(y)}{1\mp\tan(x)\tan(y)}\\\\ \text{double angle:}\\ \sin(2x)=2\sin(x)\cos(x)\\ \cos(2x)=\cos^2(x)-\sin^2(x)\\ \cos(2x)=2\cos^2(x)-1=1-2\sin^2(x)\\ \tan(2x)=\tfrac{2\tan(x)}{1-\tan^2(x)}\\\\ \text{sum-to-product and product-to-sum:}\\ \cos(x)+\cos(y)=2\cos(\tfrac{x+y}2)\cos(\tfrac{x-y}2)\\ \cos(x)-\cos(y)=-2\sin(\tfrac{x+y}2)\sin(\tfrac{x-y}2)\\ \sin(x)\pm\sin(y)=2\sin(\tfrac{x\pm y}2)\cos(\tfrac{x\mp y}2)\\ 2\sin(x)\sin(y)=\cos(x-y)-\cos(x+y)\\ 2\sin(x)\cos(y)=\sin(x+y)+\sin(x-y)\\ 2\cos(x)\cos(y)=\cos(x+y)+\cos(x-y)\\\\ \text{Hope you find whatever identities you need!}}