Editing MultiVCheatSheetOfDOOM
This is the MultiVCheatSheetOfDOOM, taken from a lecture handout by Professor Hermann Gluck of U. Penn., who apparently stole it from some electrodynamics book. It has been [[LaTeX]]ed and math-convention-ified by MicahSmukler; see Micah if you want a copy of the cheat sheet but don't want to deal with LaTeX. Disclaimer: some professors' test policies may not permit the use of this on tests, as you didn't make it. Using it on homework should be okay, though. \documentclass{article} \addtolength{\hoffset}{-35pt} \addtolength{\textwidth}{70pt} \renewcommand{\i}{\hat{i}} \renewcommand{\j}{\hat{j}} \renewcommand{\k}{\hat{k}} \renewcommand{\r}{\hat{r}} \renewcommand{\th}{\hat{\theta}} \renewcommand{\v}{\mathbf{v}} \newcommand{\ph}{\hat{\phi}} \newcommand{\z}{\hat{z}} \newcommand{\rh}{\hat{\rho}} \newcommand{\A}{\mathbf{A}} \newcommand{\B}{\mathbf{B}} \newcommand{\C}{\mathbf{C}} \newcommand{\dd}[1]{\frac{\partial}{\partial #1}} \renewcommand{\d}[2]{\frac{\partial #1}{\partial #2}} \begin{document} \begin{center} {\bf Vector Identities} \end{center} {\bf Triple Products} \begin{itemize} \item $\A \cdot (\B \times \C)=\B \cdot(\C \times \A)=\C \cdot (\A \times \B)$ \item $\A \times (\B \times \C)=\B(\A \cdot \C)-\C(\A \cdot \B)$ \end{itemize} {\bf Product Rules} \begin{itemize} \item $\nabla(fg)=f(\nabla g)+g(\nabla f)$ \item $\nabla(\A \cdot \B)=\A \times (\nabla \times \B)+\B \times(\nabla \times \A) +(\A \cdot \nabla)\B+(\B \cdot \nabla)\A$ \item $\nabla \cdot(f\A)=f(\nabla \cdot \A)+\A \cdot (\nabla f)$ \item $\nabla \cdot (\A \times \B)=\B \cdot(\nabla \times \A)-\A \cdot (\nabla \times \B)$ \item $\nabla \times (f \A)=f(\nabla \times \A)-\A \times(\nabla f)$ \item $\nabla \times (\A \times \B)=(\B \cdot \nabla)\A-(\A \cdot \nabla)\B+\A(\nabla \cdot \B) -\B(\nabla \cdot \A)$ \end{itemize} {\bf Second Derivatives} \begin{itemize} \item $\nabla \cdot (\nabla \times \A)=0$ \item $\nabla \times (\nabla f)=0$ \item $\nabla \times (\nabla \times \A)=\nabla(\nabla \cdot \A)-\nabla^2 \A$ \end{itemize} \begin{center} {\bf Vector Derivatives} \end{center} {\bf Cartesian} \begin{itemize} \item $dl=dx \, \i+dy \, \j+dz \, \k$; $d\tau=dx \, dy \, dz$ \item Gradient: $$\nabla t=\d{t}{x} \i + \d{t}{y} \j + \d{t}{z} \k$$ \item Divergence: $$\nabla \cdot \v=\d{v_x}{x} + \d{v_y}{y} + \d{v_z}{z}$$ \item Curl: $$\nabla \times \mathbf{v}=\left(\d{v_z}{y}-\d{v_y}{z}\right) \i + \left(\d{v_x}{\z}-\d{v_z}{x}\right) \j + \left(\d{v_y}{x}-\d{v_x}{y}\right) \k$$ \item Laplacian: $$\nabla^2 t=\d{^2 t}{x^2}+\d{^2 t}{y^2}+\d{^2 t}{z^2}$$ \end{itemize} \newpage {\bf Spherical} \begin{itemize} \item $dl=d\rho \, \rh + r\, d\phi \, \ph + \rho \sin \phi \, d\theta \, \th$; $d\tau=\rho^2 \sin \phi \, d\rho \, d\theta \, d\phi$ \item Gradient: $$\nabla t=\d{t}{\rho} \rh +\frac{1}{\rho} \d{t}{\phi} \ph +\frac{1}{\rho \sin \phi} \d{t}{\theta} \th$$ \item Divergence: $$\nabla \cdot \v=\frac{1}{\rho^2} \dd{\rho} (\rho^2 v_\rho) + \frac{1}{\rho \sin \phi} \dd{\phi} (v_\phi \sin \phi) + \frac{1}{\rho \sin \phi} \d{v_\theta}{\theta}$$ \item Curl: $$\nabla \times \v=\frac{1}{\rho^2} \left[\dd{\phi}(\sin \phi v_\theta)-\d{v_\phi}{\theta}\right] \rh + \frac{1}{\rho}\left[\frac{1}{\sin \phi} \d{v_\rho}{\theta}-\dd{\rho}(\rho v_\theta) \right] \ph + \frac{1}{\rho}\left[\dd{\rho}(\rho v_\phi)-\d{v_\rho}{\phi}\right] \th$$ \item Laplacian: $$\nabla^2 t=\frac{1}{\rho^2} \dd{\rho}\left(\rho^2 \d{t}{\rho}\right) + \frac{1}{\rho^2 \sin \phi} \dd{\phi}\left(\sin \phi \d{t}{\phi}\right) + \frac{1}{\rho^2 \sin^2 \phi} \d{^2 t}{\theta^2}$$ \end{itemize} {\bf Cylindrical} \begin{itemize} \item $dl=dr \, \r + r \, d\theta \, \th + dz \z$; $d\tau=r \, dr \, d\theta \, dz$ \item Gradient: $$\nabla t=\d{t}{r} \r + \frac{1}{r} \d{t}{\theta} \th + \d{t}{z} \z$$ \item Divergence: $$\nabla \cdot \v=\frac{1}{r} \dd{r} (rv_r)+\frac{1}{r} \d{v_\theta}{\theta}+\d{v_z}{z}$$ \item Curl: $$\nabla \times \v=\left[\frac{1}{r} \d{v_z}{\theta}-\d{v_\theta}{z}\right]\r + \left[\d{v_r}{z}-\d{v_z}{r}\right] \th+\frac{1}{r}\left[\dd{r}(rv_\theta)-\d{v_r}{\theta}\right] \z$$ \item Laplacian: $$\nabla^2 t=\frac{1}{r}\dd{r}\left(r\d{t}{r}\right)+\frac{1}{r^2}\d{^2 t}{\theta^2}+\d{^2 t}{z^2}$$ \end{itemize} \end{document}
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