\usepackage{harpoon}
\usepackage{tabularx}
\usepackage[dvipsnames, table]{xcolor}
+\usepackage{blindtext}
\usepackage{graphicx}
\usepackage{wrapfig}
\usepackage{tikz}
+\usepackage{tikz-3dplot}
+\usepackage{pgfplots}
\usetikzlibrary{calc}
+\usetikzlibrary{angles}
+\usetikzlibrary{datavisualization.formats.functions}
+\usetikzlibrary{decorations.markings}
\usepgflibrary{arrows.meta}
\usepackage{fancyhdr}
\pagestyle{fancy}
\newcolumntype{R}[1]{>{\hsize=#1\hsize\raggedleft\arraybackslash}X}%
\definecolor{cas}{HTML}{e6f0fe}
\linespread{1.5}
+\newcommand{\midarrow}{\tikz \draw[-triangle 90] (0,0) -- +(.1,0);}
\begin{document}
\subsection*{Operations}
- \begin{tabularx}{\columnwidth}{R{0.33}|X|X}
+\definecolor{shade1}{HTML}{ffffff}
+\definecolor{shade2}{HTML}{e6f2ff}
+ \definecolor{shade3}{HTML}{cce2ff}
+ \begin{tabularx}{\columnwidth}{r|X|X}
& \textbf{Cartesian} & \textbf{Polar} \\
\hline
\(z_1 \pm z_2\) & \((a \pm c)(b \pm d)i\) & convert to \(a+bi\)\\
\hline
- \(+k \times z\) & \multirow{2}{\hsize}{\(ka \pm kbi\)} & \(kr\operatorname{cis} \theta\)\\
+ \(+k \times z\) & \multirow{2}{*}{\(ka \pm kbi\)} & \(kr\operatorname{cis} \theta\)\\
\cline{1-1}\cline{3-3}
\(-k \times z\) & & \(kr \operatorname{cis}(\theta\pm \pi)\)\\
\hline
\[k\left(r \operatorname{cis}\theta\right)=kr \operatorname{cis}\theta\]
\noindent For \(k \in \mathbb{R}^-\):
- \[k\left(r \operatorname{cis}\theta\right)=kr \operatorname{cis}\left(\begin{cases}\theta - \pi & 0<\operatorname{Arg}(z)\le \pi \\ \theta + \pi & -\pi<\operatorname{Arg}(z)\le 0\end{cases}\right)\]
+ \[k\left(r \operatorname{cis}\theta\right)=kr \operatorname{cis}\left(\begin{cases}\theta - \pi & |0<\operatorname{Arg}(z)\le \pi \\ \theta + \pi & |-\pi<\operatorname{Arg}(z)\le 0\end{cases}\right)\]
\subsection*{Conjugate}
&= r \operatorname{cis}(-\theta)
\end{align*}
- \noindent \colorbox{cas}{On CAS:} \verb|conjg(a+bi)|
+ \noindent \colorbox{cas}{On CAS: \texttt{conjg(a+bi)}}
\subsubsection*{Properties}
\begin{itemize}
\item{\(r=|z|=\sqrt{\operatorname{Re}(z)^2 + \operatorname{Im}(z)^2}\)}
- \item{\(\theta = \operatorname{arg}(z)\) \quad \colorbox{cas}{On CAS:} \verb|arg(a+bi)|}
+ \item{\(\theta = \operatorname{arg}(z)\) \quad \colorbox{cas}{On CAS: \texttt{arg(a+bi)}}}
\item{\(\operatorname{Arg}(z) \in (-\pi,\pi)\) \quad \bf{(principal argument)}}
\item{\colorbox{cas}{Convert on CAS:}\\ \verb|compToTrig(a+bi)| \(\iff\) \verb|cExpand{r·cisX}|}
\item{Multiple representations:\\\(r\operatorname{cis}\theta=r\operatorname{cis}(\theta+2n\pi)\) with \(n \in \mathbb{Z}\) revolutions}
\begin{itemize}
\item{\(\operatorname{Re}(z)=c\) or \(\operatorname{Im}(z)=c\) (perpendicular bisector)}
\item{\(\operatorname{Im}(z)=m\operatorname{Re}(z)\)}
- \item{\(|z+a|=|z+b| \implies 2(a-b)x=b^2-a^2\)}
+ \item{\(|z+a|=|z+b| \implies 2(a-b)x=b^2-a^2\)\\Geometric: equidistant from \(a,b\)}
\end{itemize}
\subsubsection*{Circles}
\begin{itemize}
\item \(|z-z_1|^2=c^2|z_2+2|^2\)
- \item \(|z-(a+bi)|=c\)
+ \item \(|z-(a+bi)|=c \implies (x-a)^2+_(y-b)^2=c^2\)
\end{itemize}
\noindent \textbf{Loci} \qquad \(\operatorname{Arg}(z)<\theta\)
\begin{scope}
\path[clip] (0,0) -- (1,1) -- (1,0);
\fill[red, opacity=0.5, draw=black] (0,0) circle (2mm);
- \node at ($(0,0)+(20:3mm)$) {$\theta$};
+ \node at ($(0,0)+(20:3mm)$) {$\frac{\pi}{4}$};
\end{scope}
- \node [font=\footnotesize] at (0.5,-0.25) {\(\operatorname{Arg}(z)<\theta\)};
+ \node [font=\footnotesize] at (0.5,-0.25) {\(\operatorname{Arg}(z)\le\frac{\pi}{4}\)};
\node [blue, mydot] {};
\end{tikzpicture}\end{center}
\end{tikzpicture}\end{center}
\section{Vectors}
+\begin{center}\begin{tikzpicture}
+ \draw [->] (-0.5,0) -- (3,0) node [right] {\(x\)};
+ \draw [->] (0,-0.5) -- (0,3) node [above] {\(y\)};
+ \draw [orange, ->, thick] (0.5,0.5) -- (2.5,2.5) node [pos=0.5, above] {\(\vec{u}\)};
+ \begin{scope}[very thick, every node/.style={sloped,allow upside down}]
+ \draw [gray, dashed, thick] (0.5,0.5) -- (2.5,0.5) node [pos=0.5] {\midarrow} node[black, pos=0.5, below]{\(x\vec{i}\)};
+ \draw [gray, dashed, thick] (2.5,0.5) -- (2.5,2.5) node [pos=0.5] {\midarrow};
+ \end{scope}
+ \node[black, right] at (2.5,1.5) {\(y\vec{j}\)};
+\end{tikzpicture}\end{center}
+\subsection*{Column notation}
+
+\[\begin{bmatrix}x\\ y \end{bmatrix} \iff x\boldsymbol{i} + y\boldsymbol{j}\]
+\(\begin{bmatrix}x_2-x_1\\ y_2-y_1 \end{bmatrix}\) \quad between \(A(x_1,y_1), \> B(x_2,y_2)\)
+
+\subsection*{Scalar multiplication}
+
+\[k\cdot (x\boldsymbol{i}+y\boldsymbol{j})=kx\boldsymbol{i}+ky\boldsymbol{j}\]
+
+\noindent For \(k \in \mathbb{R}^-\), direction is reversed
+
+\subsection*{Vector addition}
+\begin{center}\begin{tikzpicture}[scale=1]
+ \coordinate (A) at (0,0);
+ \coordinate (B) at (2,2);
+ \draw [->, thick, red] (0,0) -- (2,2) node [pos=0.5, below right] {\(\vec{u}=2\vec{i}+2\vec{j}\)};
+ \draw [->, thick, blue] (2,2) -- (1,4) node [pos=0.5, above right] {\(\vec{v}=-\vec{i}+2\vec{j}\)};
+ \draw [->, thick, orange] (0,0) -- (1,4) node [pos=0.5, left] {\(\vec{u}+\vec{v}=\vec{i}+4\vec{j}\)};
+\end{tikzpicture}\end{center}
+
+\[(x\boldsymbol{i}+y\boldsymbol{j}) \pm (a\boldsymbol{i}+b\boldsymbol{j})=(x \pm a)\boldsymbol{i}+(y \pm b)\boldsymbol{j}\]
+\begin{itemize}
+ \item Draw each vector head to tail then join lines
+ \item Addition is commutative (parallelogram)
+ \item \(\boldsymbol{u}-\boldsymbol{v}=\boldsymbol{u}+(-\boldsymbol{v}) \implies \overrightharp{AB}=\boldsymbol{b}-\boldsymbol{a}\)
+\end{itemize}
+
+\subsection*{Magnitude}
+
+\[|(x\boldsymbol{i} + y\boldsymbol{j})|=\sqrt{x^2+y^2}\]
+
+\subsection*{Parallel vectors}
+
+\[\boldsymbol{u} || \boldsymbol{v} \iff \boldsymbol{u} = k \boldsymbol{v} \text{ where } k \in \mathbb{R} \setminus \{0\}\]
+
+For parallel vectors \(\boldsymbol{a}\) and \(\boldsymbol{b}\):\\
+\[\boldsymbol{a \cdot b}=\begin{cases}
+|\boldsymbol{a}||\boldsymbol{b}| \hspace{2.8em} \text{if same direction}\\
+-|\boldsymbol{a}||\boldsymbol{b}| \hspace{2em} \text{if opposite directions}
+\end{cases}\]
+%\includegraphics[width=0.2,height=\textheight]{graphics/parallelogram-vectors.jpg}
+%\includegraphics[width=1]{graphics/vector-subtraction.jpg}
+
+\subsection*{Perpendicular vectors}
+
+\[\boldsymbol{a} \perp \boldsymbol{b} \iff \boldsymbol{a} \cdot \boldsymbol{b} = 0\ \quad \text{(since \(\cos 90 = 0\))}\]
+
+\subsection*{Unit vector \(|\hat{\boldsymbol{a}}|=1\)}
+\[\begin{split}\hat{\boldsymbol{a}} & = {\frac{1}{|\boldsymbol{a}|}}\boldsymbol{a} \\ & = \boldsymbol{a} \cdot {|\boldsymbol{a}|}\end{split}\]
+
+ \subsection*{Scalar product \(\boldsymbol{a} \cdot \boldsymbol{b}\)}
+
+
+\begin{center}\begin{tikzpicture}[scale=2]
+ \draw [->] (0,0) -- (1,0.5) node [pos=0.5, above left] {\(\boldsymbol{b}\)};
+ \draw [->] (0,0) -- (1,0) node [pos=0.5, below] {\(\boldsymbol{a}\)};
+ \begin{scope}
+ \path[clip] (1,0.5) -- (1,0) -- (0,0);
+ \fill[orange, opacity=0.5, draw=black] (0,0) circle (2mm);
+ \node at ($(0,0)+(15:4mm)$) {\(\theta\)};
+ \end{scope}
+\end{tikzpicture}\end{center}
+\begin{align*}\boldsymbol{a} \cdot \boldsymbol{b} &= a_1 b_1 + a_2 b_2 \\ &= |\boldsymbol{a}| |\boldsymbol{b}| \cos \theta \\ &\quad (\> 0 \le \theta \le \pi) \text{ - from cosine rule}\end{align*}
+\noindent\colorbox{cas}{On CAS: \texttt{dotP({[}a\ b\ c{]},\ {[}d\ e\ f{]})}}
+
+\subsubsection*{Properties}
+
+\begin{enumerate}
+\item
+ \(k(\boldsymbol{a\cdot b})=(k\boldsymbol{a})\cdot \boldsymbol{b}=\boldsymbol{a}\cdot (k\boldsymbol{b})\)
+\item
+ \(\boldsymbol{a \cdot 0}=0\)
+\item
+ \(\boldsymbol{a} \cdot (\boldsymbol{b} + \boldsymbol{c})=\boldsymbol{a} \cdot \boldsymbol{b} + \boldsymbol{a} \cdot \boldsymbol{c}\)
+\item
+ \(\boldsymbol{i \cdot i} = \boldsymbol{j \cdot j} = \boldsymbol{k \cdot k}= 1\)
+\item
+ \(\boldsymbol{a} \cdot \boldsymbol{b} = 0 \quad \implies \quad \boldsymbol{a} \perp \boldsymbol{b}\)
+\item
+ \(\boldsymbol{a \cdot a} = |\boldsymbol{a}|^2 = a^2\)
+\end{enumerate}
+
+\subsection*{Angle between vectors}
+
+\[\cos \theta = \frac{\boldsymbol{a} \cdot \boldsymbol{b}}{|\boldsymbol{a}| |\boldsymbol{b}|} = \frac{a_1 b_1 + a_2 b_2}{|\boldsymbol{a}| |\boldsymbol{b}|}\]
+
+\noindent \colorbox{cas}{On CAS:} \texttt{angle([a b c], [a b c])}
+
+(Action \(\rightarrow\) Vector \(\rightarrow\)Angle)
+
+\subsection*{Angle between vector and axis}
+
+\noindent For\(\boldsymbol{a} = a_1 \boldsymbol{i} + a_2 \boldsymbol{j} + a_3 \boldsymbol{k}\)
+which makes angles \(\alpha, \beta, \gamma\) with positive side of
+\(x, y, z\) axes:
+\[\cos \alpha = \frac{a_1}{|\boldsymbol{a}|}, \quad \cos \beta = \frac{a_2}{|\boldsymbol{a}|}, \quad \cos \gamma = \frac{a_3}{|\boldsymbol{a}|}\]
+
+\noindent \colorbox{cas}{On CAS:} \texttt{angle({[}a\ b\ c{]},\ {[}1\ 0\ 0{]})}\\for angle
+between \(a\boldsymbol{i} + b\boldsymbol{j} + c\boldsymbol{k}\) and
+\(x\)-axis
+
+\subsection*{Projections \& resolutes}
+
+\begin{tikzpicture}[scale=3]
+ \draw [->, purple] (0,0) -- (1,0.5) node [pos=0.5, above left] {\(\boldsymbol{a}\)};
+ \draw [->, orange] (0,0) -- (1,0) node [pos=0.5, below] {\(\boldsymbol{u}\)};
+ \draw [->, blue] (1,0) -- (2,0) node [pos=0.5, below] {\(\boldsymbol{b}\)};
+ \begin{scope}
+ \path[clip] (1,0.5) -- (1,0) -- (0,0);
+ \fill[orange, opacity=0.5, draw=black] (0,0) circle (2mm);
+ \node at ($(0,0)+(15:4mm)$) {\(\theta\)};
+ \end{scope}
+ \begin{scope}[very thick, every node/.style={sloped,allow upside down}]
+ \draw [gray, dashed, thick] (1,0) -- (1,0.5) node [pos=0.5] {\midarrow} node[black, pos=0.5, right, rotate=-90]{\(\boldsymbol{w}\)};
+ \end{scope}
+\draw (0,0) coordinate (O)
+ (1,0) coordinate (A)
+ (1,0.5) coordinate (B)
+ pic [draw,red,angle radius=2mm] {right angle = O--A--B};
+\end{tikzpicture}
+
+\subsubsection*{\(\parallel\boldsymbol{b}\) (vector projection/resolute)}
+
+\begin{align*}
+ \boldsymbol{u} & = \frac{\boldsymbol{a}\cdot\boldsymbol{b}}{|\boldsymbol{b}|^2}\boldsymbol{b} \\
+ & = \left(\frac{\boldsymbol{a}\cdot\boldsymbol{b}}{|\boldsymbol{b}|}\right)\left(\frac{\boldsymbol{b}}{|\boldsymbol{b}|}\right) \\
+ & = (\boldsymbol{a} \cdot \hat{\boldsymbol{b}})\hat{\boldsymbol{b}}
+\end{align*}
+
+\subsubsection*{\(\perp\boldsymbol{b}\) (perpendicular projection)}
+\[\boldsymbol{w} = \boldsymbol{a} - \boldsymbol{u}\]
+
+\subsubsection*{\(|\boldsymbol{u}|\) (scalar resolute)}
+\begin{align*}
+ r_s &= |\boldsymbol{u}|\\
+ &= \boldsymbol{a} \cdot \hat{\boldsymbol{b}}\\
+ &=\frac{\boldsymbol{a}\cdot\boldsymbol{b}}{|\boldsymbol{b}|}
+\end{align*}
+
+\subsubsection*{Rectangular (\(\parallel,\perp\)) components}
+
+\[\boldsymbol{a}=\frac{\boldsymbol{a}\cdot\boldsymbol{b}}{\boldsymbol{b}\cdot\boldsymbol{b}}\boldsymbol{b}+\left(\boldsymbol{a}-\frac{\boldsymbol{a}\cdot\boldsymbol{b}}{\boldsymbol{b}\cdot\boldsymbol{b}}\boldsymbol{b}\right)\]
+
+
+\subsection*{Vector proofs}
+
+\textbf{Concurrent:} intersection of \(\ge\) 3 lines
+
+\begin{tikzpicture}
+ \draw [blue] (0,0) -- (1,1);
+ \draw [red] (1,0) -- (0,1);
+ \draw [brown] (0.4,0) -- (0.6,1);
+ \filldraw (0.5,0.5) circle (2pt);
+\end{tikzpicture}
+
+\subsubsection*{Collinear points}
+
+\(\ge\) 3 points lie on the same line
+
+\begin{tikzpicture}
+ \draw [purple] (0,0) -- (4,1);
+ \filldraw (2,0.5) circle (2pt) node [above] {\(C\)};
+ \filldraw (1,0.25) circle (2pt) node [above] {\(A\)};
+ \filldraw (3,0.75) circle (2pt) node [above] {\(B\)};
+ \coordinate (O) at (2.8,-0.2);
+ \node at (O) [below] {\(O\)};
+ \begin{scope}[->, orange, thick]
+ \draw (O) -- (2,0.5) node [pos=0.5, above, font=\footnotesize, black] {\(\boldsymbol{c}\)};
+ \draw (O) -- (1,0.25) node [pos=0.5, below, font=\footnotesize, black] {\(\boldsymbol{a}\)};
+ \draw (O) -- (3,0.75) node [pos=0.5, right, font=\footnotesize, black] {\(\boldsymbol{b}\)};
+ \end{scope}
+\end{tikzpicture}
+
+\begin{align*}
+ \text{e.g. Prove that}\\
+ \overrightharp{AC}=m\overrightharp{AB} \iff \boldsymbol{c}&=(1-m)\boldsymbol{a}+m\boldsymbol{b}\\
+ \implies \boldsymbol{c} &= \overrightharp{OA} + \overrightharp{AC}\\
+ &= \overrightharp{OA} + m\overrightharp{AB}\\
+ &=\boldsymbol{a}+m(\boldsymbol{b}-\boldsymbol{a})\\
+ &=\boldsymbol{a}+m\boldsymbol{b}-m\boldsymbol{a}\\
+ &=(1-m)\boldsymbol{a}+m{b}
+\end{align*}
+\begin{align*}
+ \text{Also, } \implies \overrightharp{OC} &= \lambda \vec{OA} + \mu \overrightharp{OB} \\
+ \text{where } \lambda + \mu &= 1\\
+ \text{If } C \text{ lies along } \overrightharp{AB}, & \implies 0 < \mu < 1
+\end{align*}
+
+
+\subsubsection*{Parallelograms}
+
+\begin{center}\begin{tikzpicture}
+ \coordinate (O) at (0,0) node [below left] {\(O\)};
+ \coordinate (A) at (4,0);
+ \coordinate (B) at (6,2);
+ \coordinate (C) at (2,2);
+ \coordinate (D) at (6,0);
+
+ \draw[postaction={decorate}, decoration={markings, mark=at position 0.6 with {\arrow{>>}}}] (O)--(A) node [below left] {\(A\)};
+ \draw[postaction={decorate}, decoration={markings,mark=at position 0.5 with {\arrow{>}}}] (A)--(B) node [above right] {\(B\)};
+ \draw[postaction={decorate}, decoration={markings, mark=at position 0.6 with {\arrow{>>}}}] (B)--(C) node [above left] {\(C\)};
+ \draw[postaction={decorate}, decoration={markings,mark=at position 0.5 with {\arrow{>}}}] (C)--(O);
+
+ \draw [gray, dashed] (O) -- (B) node [pos=0.75] {\(\diagdown\diagdown\)} node [pos=0.25] {\(\diagdown\diagdown\)};
+ \draw [gray, dashed] (A) -- (C) node [pos=0.75] {\(\diagup\)} node [pos=0.25] {\(\diagup\)};
+ \begin{scope}
+ \path[clip] (C) -- (A) -- (O);
+ \fill[orange, opacity=0.5, draw=black] (0,0) circle (4mm);
+ \node at ($(0,0)+(20:8mm)$) {\(\theta\)};
+ \end{scope}
+ \draw [gray, thick, dotted] (B) -- (D) node [pos=0.5, right, black, font=\footnotesize] {\(|\boldsymbol{c}|\sin\theta\)} (A) -- (D) node [pos=0.5, below, black, font=\footnotesize] {\(|\boldsymbol{c}|\cos\theta\)};
+ \draw pic [draw,thick,red,angle radius=2mm] {right angle=O--D--B};
+\end{tikzpicture}\end{center}
\begin{itemize}
+ \item
+ Diagonals \(\overrightharp{OB}, \overrightharp{AC}\) bisect each other
+ \item
+ If diagonals are equal length, it is a rectangle
+ \item
+ \(|\overrightharp{OB}|^2 + |\overrightharp{CA}|^2 = |\overrightharp{OA}|^2 + |\overrightharp{AB}|^2 + |\overrightharp{CB}|^2 + |\overrightharp{OC}|^2\)
+ \item
+ Area \(=\boldsymbol{c} \cdot \boldsymbol{a}\)
+\end{itemize}
+
+ \subsubsection*{Useful vector properties}
+
+\begin{itemize}
+\item
+ \(\boldsymbol{a} \parallel \boldsymbol{b} \implies \boldsymbol{b}=k\boldsymbol{a}\) for some
+ \(k \in \mathbb{R} \setminus \{0\}\)
+\item
+ If \(\boldsymbol{a}\) and \(\boldsymbol{b}\) are parallel with at
+ least one point in common, then they lie on the same straight line
+\item
+ \(\boldsymbol{a} \perp \boldsymbol{b} \iff \boldsymbol{a} \cdot \boldsymbol{b}=0\)
+\item
+ \(\boldsymbol{a} \cdot \boldsymbol{a} = |\boldsymbol{a}|^2\)
+\end{itemize}
+
+\subsection*{Linear dependence}
+
+\(\boldsymbol{a}, \boldsymbol{b}, \boldsymbol{c}\) are linearly dependent if they are \(\nparallel\) and:
+\begin{align*}
+ 0&=k\boldsymbol{a}+l\boldsymbol{b}+m\boldsymbol{c}\\
+ \therefore \boldsymbol{c} &= m\boldsymbol{a} + n\boldsymbol{b} \quad \text{(simultaneous)}
+\end{align*}
+
+\noindent \(\boldsymbol{a}, \boldsymbol{b},\) and \(\boldsymbol{c}\) are linearly
+independent if no vector in the set is expressible as a linear
+combination of other vectors in set, or if they are parallel.
+
+\subsection*{Three-dimensional vectors}
+
+Right-hand rule for axes: \(z\) is up or out of page.
+
+\tdplotsetmaincoords{60}{120}
+\begin{center}\begin{tikzpicture} [scale=3, tdplot_main_coords, axis/.style={->,thick},
+vector/.style={-stealth,red,very thick},
+vector guide/.style={dashed,gray,thick}]
+
+%standard tikz coordinate definition using x, y, z coords
+\coordinate (O) at (0,0,0);
+
+%tikz-3dplot coordinate definition using x, y, z coords
+
+\pgfmathsetmacro{\ax}{1}
+\pgfmathsetmacro{\ay}{1}
+\pgfmathsetmacro{\az}{1}
+
+\coordinate (P) at (\ax,\ay,\az);
+
+%draw axes
+\draw[axis] (0,0,0) -- (1,0,0) node[anchor=north east]{$x$};
+\draw[axis] (0,0,0) -- (0,1,0) node[anchor=north west]{$y$};
+\draw[axis] (0,0,0) -- (0,0,1) node[anchor=south]{$z$};
+
+%draw a vector from O to P
+\draw[vector] (O) -- (P);
+
+%draw guide lines to components
+\draw[vector guide] (O) -- (\ax,\ay,0);
+\draw[vector guide] (\ax,\ay,0) -- (P);
+\draw[vector guide] (P) -- (0,0,\az);
+\draw[vector guide] (\ax,\ay,0) -- (0,\ay,0);
+\draw[vector guide] (\ax,\ay,0) -- (0,\ay,0);
+\draw[vector guide] (\ax,\ay,0) -- (\ax,0,0);
+\node[tdplot_main_coords,above right]
+at (\ax,\ay,\az){(\ax, \ay, \az)};
+\end{tikzpicture}\end{center}
+
+\subsection*{Parametric vectors}
+
+Parametric equation of line through point \((x_0, y_0, z_0)\) and
+parallel to \(a\boldsymbol{i} + b\boldsymbol{j} + c\boldsymbol{k}\) is:
+
+\[\begin{cases}x = x_o + a \cdot t \\ y = y_0 + b \cdot t \\ z = z_0 + c \cdot t\end{cases}\]
+
+\section{Circular functions}
+
+\(\sin(bx)\) or \(\cos(bx)\): period \(=\frac{2\pi}{b}\)
+
+\noindent \(\tan(nx)\): period \(=\frac{\pi}{n}\)\\
+\indent\indent\indent asymptotes at \(x=\frac{(2k+1)\pi}{2n} \> \vert \> k \in \mathbb{Z}\)
+
+\subsection*{Reciprocal functions}
+
+\subsubsection*{Cosecant}
+
+\[\operatorname{cosec} \theta = \frac{1}{\sin \theta} \> \vert \> \sin \theta \ne 0\]
+
+\begin{itemize}
+\item
+ \textbf{Domain} \(= \mathbb{R} \setminus {n\pi : n \in \mathbb{Z}}\)
+\item
+ \textbf{Range} \(= \mathbb{R} \setminus (-1, 1)\)
\item
- \textbf{vector:} a directed line segment\\
+ \textbf{Turning points} at
+ \(\theta = \frac{(2n + 1)\pi}{2} \> \vert \> n \in \mathbb{Z}\)
\item
- arrow indicates direction
+ \textbf{Asymptotes} at \(\theta = n\pi \> \vert \> n \in \mathbb{Z}\)
+\end{itemize}
+
+\subsubsection*{Secant}
+
+
+\begin{center}\includegraphics[width=0.7\columnwidth]{graphics/sec.png}\end{center}
+
+\[\operatorname{sec} \theta = \frac{1}{\cos \theta} \> \vert \> \cos \theta \ne 0\]
+
+\begin{itemize}
+
\item
- length indicates magnitude
+ \textbf{Domain}
+ \(= \mathbb{R} \setminus \frac{(2n + 1) \pi}{2} : n \in \mathbb{Z}\}\)
\item
- notated as \(\vec{a}, \widetilde{A}, \overrightharp{a}\)
+ \textbf{Range} \(= \mathbb{R} \setminus (-1, 1)\)
\item
- column notation: \(\begin{bmatrix} x \\ y \end{bmatrix}\)
+ \textbf{Turning points} at
+ \(\theta = n\pi \> \vert \> n \in \mathbb{Z}\)
\item
- vectors with equal magnitude and direction are equivalent
+ \textbf{Asymptotes} at
+ \(\theta = \frac{(2n + 1) \pi}{2} \> \vert \> n \in \mathbb{Z}\)
\end{itemize}
-%\includegraphics[width=0.2\textwidth,height=\textheight]{graphics/vectors-intro.png}
+\subsubsection*{Cotangent}
-\subsection{Vector addition}
+\begin{center}\includegraphics[width=0.7\columnwidth]{graphics/cot.png}\end{center}
-\(\boldsymbol{u} + \boldsymbol{v}\) can be represented by drawing each
- vector head to tail then joining the lines.\\
-Addition is commutative (parallelogram)
+\[\operatorname{cot} \theta = {{\cos \theta} \over {\sin \theta}} \> \vert \> \sin \theta \ne 0\]
-\subsection{Scalar multiplication}
+\begin{itemize}
-For \(k \in \mathbb{R}^+\), \(k\boldsymbol{u}\) has the same direction
-as \(\boldsymbol{u}\) but length is multiplied by a factor of \(k\).
+\item
+ \textbf{Domain} \(= \mathbb{R} \setminus \{n \pi: n \in \mathbb{Z}\}\)
+\item
+ \textbf{Range} \(= \mathbb{R}\)
+\item
+ \textbf{Asymptotes} at \(\theta = n\pi \> \vert \> n \in \mathbb{Z}\)
+\end{itemize}
-When multiplied by \(k < 0\), direction is reversed and length is
-multplied by \(k\).
+\subsubsection*{Symmetry properties}
-\subsection{Vector subtraction}
+\[\begin{split}
+ \operatorname{sec} (\pi \pm x) & = -\operatorname{sec} x \\
+ \operatorname{sec} (-x) & = \operatorname{sec} x \\
+ \operatorname{cosec} (\pi \pm x) & = \mp \operatorname{cosec} x \\
+ \operatorname{cosec} (-x) & = - \operatorname{cosec} x \\
+ \operatorname{cot} (\pi \pm x) & = \pm \operatorname{cot} x \\
+ \operatorname{cot} (-x) & = - \operatorname{cot} x
+\end{split}\]
-To find \(\boldsymbol{u} - \boldsymbol{v}\), add \(\boldsymbol{-v}\) to
-\(\boldsymbol{u}\)
+\subsubsection*{Complementary properties}
-\subsection{Parallel vectors}
+\[\begin{split}
+ \operatorname{sec} \left({\pi \over 2} - x\right) & = \operatorname{cosec} x \\
+ \operatorname{cosec} \left({\pi \over 2} - x\right) & = \operatorname{sec} x \\
+ \operatorname{cot} \left({\pi \over 2} - x\right) & = \tan x \\
+ \tan \left({\pi \over 2} - x\right) & = \operatorname{cot} x
+\end{split}\]
-Same or opposite direction
+\subsubsection*{Pythagorean identities}
-\[\boldsymbol{u} || \boldsymbol{v} \iff \boldsymbol{u} = k \boldsymbol{v} \text{ where } k \in \mathbb{R} \setminus \{0\}\]
+\[\begin{split}
+ 1 + \operatorname{cot}^2 x & = \operatorname{cosec}^2 x, \quad \text{where } \sin x \ne 0 \\
+ 1 + \tan^2 x & = \operatorname{sec}^2 x, \quad \text{where } \cos x \ne 0
+\end{split}\]
-\subsection{Position vectors}
+\subsection*{Compound angle formulas}
-Vectors may describe a position relative to \(O\).
+\[\cos(x \pm y) = \cos x + \cos y \mp \sin x \sin y\]
+\[\sin(x \pm y) = \sin x \cos y \pm \cos x \sin y\]
+\[\tan(x \pm y) = {{\tan x \pm \tan y} \over {1 \mp \tan x \tan y}}\]
-For a point \(A\), the position vector is \(\overrightharp{OA}\)
+\subsection*{Double angle formulas}
-\subsection{Linear combinations of non-parallel
-vectors}
+\[\begin{split}
+ \cos 2x &= \cos^2 x - \sin^2 x \\
+ & = 1 - 2\sin^2 x \\
+ & = 2 \cos^2 x -1
+\end{split}\]
-If two non-zero vectors \(\boldsymbol{a}\) and \(\boldsymbol{b}\) are
-not parallel, then:
+\[\sin 2x = 2 \sin x \cos x\]
-\[m\boldsymbol{a} + n\boldsymbol{b} = p \boldsymbol{a} + q \boldsymbol{b}\quad \therefore \quad m = p, \> n = q\]
+\[\tan 2x = {{2 \tan x} \over {1 - \tan^2 x}}\]
-%\includegraphics[width=0.2,height=\textheight]{graphics/parallelogram-vectors.jpg}
-%\includegraphics[width=1]{graphics/vector-subtraction.jpg}
+\subsection*{Inverse circular functions}
-\subsection{Column vector notation}
+Inverse functions: \(f(f^{-1}(x)) = x, \quad f(f^{-1}(x)) = x\)\\
+Must be 1:1 to find inverse (reflection in \(y=x\)).\\
+Domain is restricted to make functions 1:1.
-A vector between points \(A(x_1,y_1), \> B(x_2,y_2)\) can be represented
-as \(\begin{bmatrix}x_2-x_1\\ y_2-y_1 \end{bmatrix}\)
+\[\sin^{-1}: [-1, 1] \rightarrow \mathbb{R}, \quad \sin^{-1} x = y\]
+\hfill where \(\sin y = x, \> y \in [{-\pi \over 2}, {\pi \over 2}]\)
-\subsection{Component notation}
+\[\cos^{-1}: [-1,1] \rightarrow \mathbb{R}, \quad \cos^{-1} x = y\]
+\hfill where \(\cos y = x, \> y \in [0, \pi]\)
-A vector \(\boldsymbol{u} = \begin{bmatrix}x\\ y \end{bmatrix}\) can be
-written as \(\boldsymbol{u} = x\boldsymbol{i} + y\boldsymbol{j}\).\\
-\(\boldsymbol{u}\) is the sum of two components \(x\boldsymbol{i}\) and
-\(y\boldsymbol{j}\)\\
-Magnitude of vector
-\(\boldsymbol{u} = x\boldsymbol{i} + y\boldsymbol{j}\) is denoted by
-\(|u|=\sqrt{x^2+y^2}\)
+\[\tan^{-1}: \mathbb{R} \rightarrow \mathbb{R}, \quad \tan^{-1} x = y\]
+\hfill where \(\tan y = x, \> y \in \left(-{\pi \over 2}, {\pi \over 2}\right)\)
-Basic algebra applies:\\
-\((x\boldsymbol{i} + y\boldsymbol{j}) + (m\boldsymbol{i} + n\boldsymbol{j}) = (x + m)\boldsymbol{i} + (y+n)\boldsymbol{j}\)\\
-Two vectors equal if and only if their components are equal.
-\subsection{Unit vector \(|\hat{\boldsymbol{a}}|=1\)}
-\begin{equation}\begin{split}\hat{\boldsymbol{a}} & = {1 \over {|\boldsymbol{a}|}}\boldsymbol{a} \\ & = \boldsymbol{a} \cdot {|\boldsymbol{a}|}\end{split}\end{equation}
+\section{Differential calculus}
- \subsection*{Scalar/dot product \(\boldsymbol{a} \cdot \boldsymbol{b}\)}
+\subsection*{Limits}
-\[\boldsymbol{a} \cdot \boldsymbol{b} = a_1 b_1 + a_2 b_2\]
+\[\lim_{x \rightarrow a}f(x)\]
+\(L^-,\quad L^+\) \qquad limit from below/above\\
+\(\lim_{x \to a} f(x)\) \quad limit of a point\\
-\textbf{on CAS:} \texttt{dotP({[}a\ b\ c{]},\ {[}d\ e\ f{]})}
+\noindent For solving \(x\rightarrow\infty\), put all \(x\) terms in denominators\\
+ e.g. \[\lim_{x \rightarrow \infty}{{2x+3} \over {x-2}}={{2+{3 \over x}} \over {1-{2 \over x}}}={2 \over 1} = 2\]
-\subsection{Scalar product properties}
+\subsubsection*{Limit theorems}
\begin{enumerate}
\item
- \(k(\boldsymbol{a\cdot b})=(k\boldsymbol{a})\cdot \boldsymbol{b}=\boldsymbol{a}\cdot (k\boldsymbol{b})\)
-\item
- \(\boldsymbol{a \cdot 0}=0\)
+ For constant function \(f(x)=k\), \(\lim_{x \rightarrow a} f(x) = k\)
\item
- \(\boldsymbol{a \cdot (b + c)}=\boldsymbol{a \cdot b + a \cdot c}\)
+ \(\lim_{x \rightarrow a} (f(x) \pm g(x)) = F \pm G\)
\item
- \(\boldsymbol{i \cdot i} = \boldsymbol{j \cdot j} = \boldsymbol{k \cdot k}= 1\)
+ \(\lim_{x \rightarrow a} (f(x) \times g(x)) = F \times G\)
+ \item
+\(\therefore \lim_{x \rightarrow a} c \times f(x)=cF\) where \(c=\) constant
\item
- If \(\boldsymbol{a} \cdot \boldsymbol{b} = 0\), \(\boldsymbol{a}\) and
- \(\boldsymbol{b}\) are perpendicular
+ \({\lim_{x \rightarrow a} {f(x) \over g(x)}} = {F \over G}, G \ne 0\)
\item
- \(\boldsymbol{a \cdot a} = |\boldsymbol{a}|^2 = a^2\)
+ \(f(x)\) is continuous \(\iff L^-=L^+=f(x) \> \forall x\)
\end{enumerate}
-For parallel vectors \(\boldsymbol{a}\) and \(\boldsymbol{b}\):\\
-\[\boldsymbol{a \cdot b}=\begin{cases}
-|\boldsymbol{a}||\boldsymbol{b}| \hspace{2.8em} \text{if same direction}\\
--|\boldsymbol{a}||\boldsymbol{b}| \hspace{2em} \text{if opposite directions}
-\end{cases}\]
+\subsection*{Gradients of secants and tangents}
+
+\textbf{Secant (chord)} - line joining two points on curve\\
+\textbf{Tangent} - line that intersects curve at one point
+
+\subsection*{First principles derivative}
+
+\[f^\prime(x) = \lim_{\delta x \rightarrow 0}{\delta y \over \delta x}={\frac{dy}{dx}}\]
+
+\subsubsection*{Logarithmic identities}
+
+\(\log_b (xy)=\log_b x + \log_b y\)\\
+\(\log_b x^n = n \log_b x\)\\
+\(\log_b y^{x^n} = x^n \log_b y\)
+
+\subsubsection*{Index identities}
+
+\(b^{m+n}=b^m \cdot b^n\)\\
+\((b^m)^n=b^{m \cdot n}\)\\
+\((b \cdot c)^n = b^n \cdot c^n\)\\
+\({a^m \div a^n} = {a^{m-n}}\)
+
+\subsection*{Derivative rules}
+
+\renewcommand{\arraystretch}{1.4}
+\begin{tabularx}{\columnwidth}{rX}
+ \hline
+\(f(x)\) & \(f^\prime(x)\)\\
+\hline
+\(\sin x\) & \(\cos x\)\\
+\(\sin ax\) & \(a\cos ax\)\\
+\(\cos x\) & \(-\sin x\)\\
+\(\cos ax\) & \(-a \sin ax\)\\
+\(\tan f(x)\) & \(f^2(x) \sec^2f(x)\)\\
+\(e^x\) & \(e^x\)\\
+\(e^{ax}\) & \(ae^{ax}\)\\
+\(ax^{nx}\) & \(an \cdot e^{nx}\)\\
+ \(\log_e x\) & \(\dfrac{1}{x}\)\\
+ \(\log_e {ax}\) & \(\dfrac{1}{x}\)\\
+ \(\log_e f(x)\) & \(\dfrac{f^\prime (x)}{f(x)}\)\\
+\(\sin(f(x))\) & \(f^\prime(x) \cdot \cos(f(x))\)\\
+ \(\sin^{-1} x\) & \(\dfrac{1}{\sqrt{1-x^2}}\)\\
+ \(\cos^{-1} x\) & \(\dfrac{-1}{sqrt{1-x^2}}\)\\
+ \(\tan^{-1} x\) & \(\dfrac{1}{1 + x^2}\)\\
+ \hline
+\end{tabularx}
+
+\subsection*{Reciprocal derivatives}
+
+\[\frac{1}{\frac{dy}{dx}} = \frac{dx}{dy}\]
+
+\subsection*{Differentiating \(x=f(y)\)}
+\begin{align*}
+ \text{Find }& \frac{dx}{dy}\\
+ \text{Then, }\frac{dx}{dy} &= \frac{1}{\frac{dy}{dx}} \\
+ \implies {\frac{dy}{dx}} &= \frac{1}{\frac{dx}{dy}}\\
+ \therefore {\frac{dy}{dx}} &= \frac{1}{\frac{dx}{dy}}
+\end{align*}
+
+\subsection*{Second derivative}
+\begin{align*}f(x) \longrightarrow &f^\prime (x) \longrightarrow f^{\prime\prime}(x)\\
+\implies y \longrightarrow &\frac{dy}{dx} \longrightarrow \frac{d^2 y}{dx^2}\end{align*}
+
+\noindent Order of polynomial \(n\)th derivative decrements each time the derivative is taken
+
+\subsubsection*{Points of Inflection}
+
+\emph{Stationary point} - i.e.
+\(f^\prime(x)=0\)\\
+\emph{Point of inflection} - max \(|\)gradient\(|\) (i.e.
+\(f^{\prime\prime} = 0\))
+%\begin{table*}[ht]
+%\centering
+% \begin{tabularx}{\textwidth}{XXXX}
+%\hline
+% \rowcolor{shade2}
+% & \(\dfrac{d^2 y}{dx^2} > 0\) & \(\dfrac{d^2y}{dx^2}<0\) & \(\dfrac{d^2y}{dx^2}=0\) (inflection) \\
+%\hline
+% \(\frac{dy}{dx}>0\) & \begin{tikzpicture} \draw[domain=1:2,smooth,variable=\x,blue] plot ({\x},{(1/10)*\x*\x*\x}) plot ({\x},{0.675*\x-0.677}); \end{tikzpicture} & cell 3\\
+%cell 1 & cell 2 & cell 3\\
+%\hline
+%\end{tabularx}
+%\end{table*}
+\begin{itemize}
+
+\item
+ if \(f^\prime (a) = 0\) and \(f^{\prime\prime}(a) > 0\), then point
+ \((a, f(a))\) is a local min (curve is concave up)
+\item
+ if \(f^\prime (a) = 0\) and \(f^{\prime\prime} (a) < 0\), then point
+ \((a, f(a))\) is local max (curve is concave down)
+\item
+ if \(f^{\prime\prime}(a) = 0\), then point \((a, f(a))\) is a point of
+ inflection
+\item
+ if also \(f^\prime(a)=0\), then it is a stationary point of inflection
+\end{itemize}
-\subsection{Geometric scalar products}
+\begin{table*}[ht]
+ \centering
+ \includegraphics[width=0.7\textwidth]{graphics/second-derivatives.png}
+\end{table*}
-\[\boldsymbol{a} \cdot \boldsymbol{b} = |\boldsymbol{a}| |\boldsymbol{b}| \cos \theta\]
+\subsection*{Implicit Differentiation}
-where \(0 \le \theta \le \pi\)
+\noindent Used for differentiating circles etc.
-\subsection{Perpendicular vectors}
+If \(p\) and \(q\) are expressions in \(x\) and \(y\) such that \(p=q\),
+for all \(x\) and \(y\), then:
-If \(\boldsymbol{a} \cdot \boldsymbol{b} = 0\), then
-\(\boldsymbol{a} \perp \boldsymbol{b}\) (since \(\cos 90 = 0\))
+\[{\frac{dp}{dx}} = {\frac{dq}{dx}} \quad \text{and} \quad {\frac{dp}{dy}} = {\frac{dq}{dy}}\]
-\subsection{Finding angle between
-vectors}
+\noindent \colorbox{cas}{\textbf{On CAS:}}\\
+Action \(\rightarrow\) Calculation \(\rightarrow\) \texttt{impDiff(y\^{}2+ax=5,\ x,\ y)}\\
+Returns \(y^\prime= \dots\).
-\textbf{positive direction}
+\subsection*{Integration}
-\[\cos \theta = {{\boldsymbol{a} \cdot \boldsymbol{b}} \over {|\boldsymbol{a}| |\boldsymbol{b}|}} = {{a_1 b_1 + a_2 b_2} \over {|\boldsymbol{a}| |\boldsymbol{b}|}}\]
+\[\int f(x) \cdot dx = F(x) + c \quad \text{where } F^\prime(x) = f(x)\]
-\textbf{on CAS:} \texttt{angle({[}a\ b\ c{]},\ {[}a\ b\ c{]})} (Action
--\textgreater{} Vector -\textgreater{} Angle)
+\subsection*{Integral laws}
-\subsection{Angle between vector and
-axis}
+\renewcommand{\arraystretch}{1.4}
+\begin{tabularx}{\columnwidth}{rX}
+\hline
+ \(f(x)\) & \(\int f(x) \cdot dx\) \\
+ \hline
+ \(k\) (constant) & \(kx + c\)\\
+ \(x^n\) & \(\dfrac{1}{n+1} x^{n+1}\) \\
+ \(a x^{-n}\) &\(a \cdot \log_e x + c\)\\
+ \(\dfrac{1}{ax+b}\) &\(\dfrac{1}{a} \log_e (ax+b) + c\)\\
+ \((ax+b)^n\) & \(\dfrac{1}{a(n+1)}(ax+b)^{n-1} + c\)\\
+ \(e^{kx}\) & \(\dfrac{1}{k} e^{kx} + c\)\\
+ \(e^k\) & \(e^kx + c\)\\
+ \(\sin kx\) & \(\dfrac{-1}{k} \cos (kx) + c\)\\
+ \(\cos kx\) & \(\frac{1}{k} \sin (kx) + c\)\\
+ \(\sec^2 kx\) & \(\frac{1}{k} \tan(kx) + c\)\\
+ \(\dfrac{1}{\sqrt{a^2-x^2}}\) & \(\sin^{-1} \dfrac{x}{a} + c \>\vert\> a>0\)\\
+ \(\dfrac{-1}{\sqrt{a^2-x^2}}\) & \(\cos^{-1} \dfrac{x}{a} + c \>\vert\> a>0\)\\
+ \(\frac{a}{a^2-x^2}\) & \(\tan^{-1} \frac{x}{a} + c\)\\
+ \(\frac{f^\prime (x)}{f(x)}\) & \(\log_e f(x) + c\)\\
+ \(g^\prime(x)\cdot f^\prime(g(x)\) & \(f(g(x))\) (chain rule)\\
+ \(f(x) \cdot g(x)\) & \(\int [f^\prime(x) \cdot g(x)] dx + \int [g^\prime(x) f(x)] dx\)\\
+ \hline
+\end{tabularx}
-Direction of a vector can be given by the angles it makes with
-\(\boldsymbol{i}, \boldsymbol{j}, \boldsymbol{k}\) directions.
+Note \(\sin^{-1} {x \over a} + \cos^{-1} {x \over a}\) is constant \(\forall x \in (-a, a)\)
-For
-\(\boldsymbol{a} = a_1 \boldsymbol{i} + a_2 \boldsymbol{j} + a_3 \boldsymbol{k}\)
-which makes angles \(\alpha, \beta, \gamma\) with positive direction of
-\(x, y, z\) axes:
-\[\cos \alpha = {a_1 \over |\boldsymbol{a}|}, \quad \cos \beta = {a_2 \over |\boldsymbol{a}|}, \quad \cos \gamma = {a_3 \over |\boldsymbol{a}|}\]
+\subsection*{Definite integrals}
-\textbf{on CAS:} \texttt{angle({[}a\ b\ c{]},\ {[}1\ 0\ 0{]})} for angle
-between \(a\boldsymbol{i} + b\boldsymbol{j} + c\boldsymbol{k}\) and
-\(x\)-axis
+\[\int_a^b f(x) \cdot dx = [F(x)]_a^b=F(b)-F(a)\]
+
+\begin{itemize}
+
+\item
+ Signed area enclosed by\\
+ \(\> y=f(x), \quad y=0, \quad x=a, \quad x=b\).
+\item
+ \emph{Integrand} is \(f\).
+\end{itemize}
+
+\subsubsection*{Properties}
-\subsection{Vector projections}
+\[\int^b_a f(x) \> dx = \int^c_a f(x) \> dx + \int^b_c f(x) \> dx\]
-Vector resolute of \(\boldsymbol{a}\) in direction of \(\boldsymbol{b}\)
-is magnitude of \(\boldsymbol{a}\) in direction of \(\boldsymbol{b}\):
+\[\int^a_a f(x) \> dx = 0\]
-\[\boldsymbol{u}={{\boldsymbol{a}\cdot\boldsymbol{b}}\over |\boldsymbol{b}|^2}\boldsymbol{b}=\left({\boldsymbol{a}\cdot{\boldsymbol{b} \over |\boldsymbol{b}|}}\right)\left({\boldsymbol{b} \over |\boldsymbol{b}|}\right)=(\boldsymbol{a} \cdot \hat{\boldsymbol{b}})\hat{\boldsymbol{b}}\]
+\[\int^b_a k \cdot f(x) \> dx = k \int^b_a f(x) \> dx\]
-\subsection{Scalar resolute of \(\boldsymbol{a}\) on \(\boldsymbol{b}\)}
+\[\int^b_a f(x) \pm g(x) \> dx = \int^b_a f(x) \> dx \pm \int^b_a g(x) \> dx\]
-\[r_s = |\boldsymbol{u}| = \boldsymbol{a} \cdot \hat{\boldsymbol{b}}\]
+\[\int^b_a f(x) \> dx = - \int^a_b f(x) \> dx\]
-\subsection{Vector resolute of \(\boldsymbol{a} \perp \boldsymbol{b}\)}
+\subsection*{Integration by substitution}
-\[\boldsymbol{w} = \boldsymbol{a} - \boldsymbol{u} \> \text{ where } \boldsymbol{u} \text{ is projection } \boldsymbol{a} \text{ on } \boldsymbol{b}\]
+\[\int f(u) {\frac{du}{dx}} \cdot dx = \int f(u) \cdot du\]
-\subsection{Vector proofs}
+\noindent Note \(f(u)\) must be 1:1 \(\implies\) one \(x\) for each \(y\)
+\begin{align*}\text{e.g. for } y&=\int(2x+1)\sqrt{x+4} \cdot dx\\
+ \text{let } u&=x+4\\
+ \implies& {\frac{du}{dx}} = 1\\
+ \implies& x = u - 4\\
+ \text{then } &y=\int (2(u-4)+1)u^{\frac{1}{2}} \cdot du\\
+ &\text{(solve as normal integral)}
+\end{align*}
-\subsubsection{Concurrent lines}
+\subsubsection*{Definite integrals by substitution}
-\(\ge\) 3 lines intersect at a single point
+For \(\int^b_a f(x) {\frac{du}{dx}} \cdot dx\), evaluate new \(a\) and
+\(b\) for \(f(u) \cdot du\).
-\subsubsection{Collinear points}
+\subsubsection*{Trigonometric integration}
-\(\ge\) 3 points lie on the same line\\
-\(\implies \vec{OC} = \lambda \vec{OA} + \mu \vec{OB}\) where
-\(\lambda + \mu = 1\). If \(C\) is between \(\vec{AB}\), then
-\(0 < \mu < 1\)\\
-Points \(A, B, C\) are collinear iff
-\(\vec{AC}=m\vec{AB} \text{ where } m \ne 0\)
+\[\sin^m x \cos^n x \cdot dx\]
-\subsubsection{Useful vector properties}
+\paragraph{\textbf{\(m\) is odd:}}
+\(m=2k+1\) where \(k \in \mathbb{Z}\)\\
+\(\implies \sin^{2k+1} x = (\sin^2 z)^k \sin x = (1 - \cos^2 x)^k \sin x\)\\
+Substitute \(u=\cos x\)
+
+\paragraph{\textbf{\(n\) is odd:}}
+\(n=2k+1\) where \(k \in \mathbb{Z}\)\\
+\(\implies \cos^{2k+1} x = (\cos^2 x)^k \cos x = (1-\sin^2 x)^k \cos x\)\\
+Substitute \(u=\sin x\)
+
+\paragraph{\textbf{\(m\) and \(n\) are even:}}
+use identities...
\begin{itemize}
+
\item
- If \(\boldsymbol{a}\) and \(\boldsymbol{b}\) are parallel, then
- \(\boldsymbol{b}=k\boldsymbol{a}\) for some
- \(k \in \mathbb{R} \setminus \{0\}\)
+ \(\sin^2x={1 \over 2}(1-\cos 2x)\)
\item
- If \(\boldsymbol{a}\) and \(\boldsymbol{b}\) are parallel with at
- least one point in common, then they lie on the same straight line
+ \(\cos^2x={1 \over 2}(1+\cos 2x)\)
\item
- Two vectors \(\boldsymbol{a}\) and \(\boldsymbol{b}\) are
- perpendicular if \(\boldsymbol{a} \cdot \boldsymbol{b}=0\)
+ \(\sin 2x = 2 \sin x \cos x\)
+\end{itemize}
+
+\subsection*{Partial fractions}
+
+\colorbox{cas}{On CAS:}\\
+\indent Action \(\rightarrow\) Transformation \(\rightarrow\)
+\texttt{expand/combine}\\
+\indent Interactive \(\rightarrow\) Transformation \(\rightarrow\)
+Expand \(\rightarrow\) Partial
+
+\subsection*{Graphing integrals on CAS}
+
+\colorbox{cas}{In main:} Interactive \(\rightarrow\) Calculation \(\rightarrow\)
+\(\int\) (\(\rightarrow\) Definite)\\
+Restrictions: \texttt{Define\ f(x)=..} then \texttt{f(x)\textbar{}x\textgreater{}..}
+
+\subsection*{Applications of antidifferentiation}
+
+\begin{itemize}
+
\item
- \(\boldsymbol{a} \cdot \boldsymbol{a} = |\boldsymbol{a}|^2\)
+ \(x\)-intercepts of \(y=f(x)\) identify \(x\)-coordinates of
+ stationary points on \(y=F(x)\)
+\item
+ nature of stationary points is determined by sign of \(y=f(x)\) on
+ either side of its \(x\)-intercepts
+\item
+ if \(f(x)\) is a polynomial of degree \(n\), then \(F(x)\) has degree
+ \(n+1\)
\end{itemize}
-\subsection{Linear dependence}
+To find stationary points of a function, substitute \(x\) value of given
+point into derivative. Solve for \({\frac{dy}{dx}}=0\). Integrate to find
+original function.
-Vectors \(\boldsymbol{a}, \boldsymbol{b}, \boldsymbol{c}\) are linearly
-dependent if they are non-parallel and:
+\subsection*{Solids of revolution}
-\[k\boldsymbol{a}+l\boldsymbol{b}+m\boldsymbol{c} = 0\]
-\[\therefore \boldsymbol{c} = m\boldsymbol{a} + n\boldsymbol{b} \quad \text{(simultaneous)}\]
+Approximate as sum of infinitesimally-thick cylinders
-\(\boldsymbol{a}, \boldsymbol{b},\) and \(\boldsymbol{c}\) are linearly
-independent if no vector in the set is expressible as a linear
-combination of other vectors in set, or if they are parallel.
+\subsubsection*{Rotation about \(x\)-axis}
-Vector \(\boldsymbol{w}\) is a linear combination of vectors
-\(\boldsymbol{v_1}, \boldsymbol{v_2}, \boldsymbol{v_3}\)
+\begin{align*}
+ V &= \int^{x=b}_{x-a} \pi y^2 \> dx \\
+ &= \pi \int^b_a (f(x))^2 \> dx
+\end{align*}
-\subsection{Three-dimensional vectors}
+\subsubsection*{Rotation about \(y\)-axis}
-Right-hand rule for axes: \(z\) is up or out of page.
+\begin{align*}
+ V &= \int^{y=b}_{y=a} \pi x^2 \> dy \\
+ &= \pi \int^b_a (f(y))^2 \> dy
+\end{align*}
-%\includegraphics{graphics/vectors-3d.png}
+\subsubsection*{Regions not bound by \(y=0\)}
-\subsection{Parametric vectors}
+\[V = \pi \int^b_a f(x)^2 - g(x)^2 \> dx\]
+\hfill where \(f(x) > g(x)\)
-Parametric equation of line through point \((x_0, y_0, z_0)\) and
-parallel to \(a\boldsymbol{i} + b\boldsymbol{j} + c\boldsymbol{k}\) is:
+\subsection*{Length of a curve}
+
+\[L = \int^b_a \sqrt{1 + ({\frac{dy}{dx}})^2} \> dx \quad \text{(Cartesian)}\]
+
+\[L = \int^b_a \sqrt{{\frac{dx}{dt}} + ({\frac{dy}{dt}})^2} \> dt \quad \text{(parametric)}\]
+
+\noindent \colorbox{cas}{On CAS:}\\
+\indent Evaluate formula,\\
+\indent or Interactive \(\rightarrow\) Calculation
+\(\rightarrow\) Line \(\rightarrow\) \texttt{arcLen}
+
+\subsection*{Rates}
+
+\subsubsection*{Gradient at a point on parametric curve}
+
+\[{\frac{dy}{dx}} = {{\frac{dy}{dt}} \div {\frac{dx}{dt}}} \> \vert \> {\frac{dx}{dt}} \ne 0\]
+
+\[\frac{d^2}{dx^2} = \frac{d(y^\prime)}{dx} = {\frac{dy^\prime}{dt} \div {\frac{dx}{dt}}} \> \vert \> y^\prime = {\frac{dy}{dx}}\]
+
+\subsection*{Rational functions}
+
+\[f(x) = \frac{P(x)}{Q(x)} \quad \text{where } P, Q \text{ are polynomial functions}\]
+
+\subsubsection*{Addition of ordinates}
+
+\begin{itemize}
+
+\item
+ when two graphs have the same ordinate, \(y\)-coordinate is double the
+ ordinate
+\item
+ when two graphs have opposite ordinates, \(y\)-coordinate is 0 i.e.
+ (\(x\)-intercept)
+\item
+ when one of the ordinates is 0, the resulting ordinate is equal to the
+ other ordinate
+\end{itemize}
+
+\subsection*{Fundamental theorem of calculus}
+
+If \(f\) is continuous on \([a, b]\), then
+
+\[\int^b_a f(x) \> dx = F(b) - F(a)\]
+\hfill where \(F = \int f \> dx\)
+
+\subsection*{Differential equations}
+
+\noindent\textbf{Order} - highest power inside derivative\\
+\textbf{Degree} - highest power of highest derivative\\
+e.g. \({\left(\dfrac{dy^2}{d^2} x\right)}^3\) \qquad order 2, degree 3
+
+\subsubsection*{Verifying solutions}
+
+Start with \(y=\dots\), and differentiate. Substitute into original
+equation.
+
+\subsubsection*{Function of the dependent
+variable}
+
+If \({\frac{dy}{dx}}=g(y)\), then
+\(\frac{dx}{dy} = 1 \div \frac{dy}{dx} = \frac{1}{g(y)}\). Integrate both sides to solve equation. Only add \(c\) on one side. Express
+\(e^c\) as \(A\).
+
+\subsubsection*{Mixing problems}
+
+\[\left(\frac{dm}{dt}\right)_\Sigma = \left(\frac{dm}{dt}\right)_{\text{in}} - \left(\frac{dm}{dt}_{\text{out}}\right)\]
+
+\subsubsection*{Separation of variables}
+
+If \({\frac{dy}{dx}}=f(x)g(y)\), then:
+
+\[\int f(x) \> dx = \int \frac{1}{g(y)} \> dy\]
+
+\subsubsection*{Euler's method for solving DEs}
-\begin{equation}\begin{cases}x = x_o + a \cdot t \\ y = y_0 + b \cdot t \\ z = z_0 + c \cdot t\end{cases}\end{equation}
+\[\frac{f(x+h) - f(x)}{h} \approx f^\prime (x) \quad \text{for small } h\]
+\[\implies f(x+h) \approx f(x) + hf^\prime(x)\]
\end{multicols}
\end{document}