\documentclass[12pt,twoside,addpoints]{exam} \usepackage{enumitem} \usepackage{amsmath} \usepackage[top=15mm,bottom=20mm,right=15mm,left=15mm]{geometry} \usepackage{hyperref} \usepackage{tkz-graph} \usepackage{multicol} \usepackage{tikz} \usepackage{caption} \usepackage{pgfplots} \usepackage{verbatim} \usepackage{amssymb} \usetikzlibrary{calc} \usetikzlibrary{arrows.meta} \DeclareMathOperator{\Dirichlet}{D} \boxedpoints \pointsinrightmargin \setlength{\rightpointsmargin}{1.5cm} \title{\vspace*{-2cm}22 Problems} \author{Aayush Bajaj} \date{\today\vspace*{-0.5cm}} \cfoot{\thepage} \noprintanswers \renewenvironment{solutionordottedlines}[1][] {% begin code \def\@tempa{#1}% \expandafter\comment } {% end code \expandafter\endcomment } \makeatother \renewenvironment{solutionorbox}[1][] {% begin code \def\@tempa{#1}% \expandafter\comment } {% end code \expandafter\endcomment } \makeatother \begin{document} \maketitle \noindent\fbox{ \parbox{\textwidth}{Welcome! Today is the $26^{th}$ of December, and it is my birthday :D.\\\\Today we are going to be playing a game called \textit{22 Problems}. This game consists of 22 (mostly) \textbf{mathematical} problems and whoever has the highest score by the deadline will be the winner! } } \bigbreak \dotfill \section*{Rules} \begin{enumerate} \item You must try to avoid using the internet. All books are fair game. \item If your work is unpleasant to read, and / or difficult to mark, I shall discard it. \item The boxed numbers in the right margin are marks. \item Deadline: \textit{11:59PM}, 31st of December 2023. \item Submission: \LaTeX{} appraised, hand-written accepted. \textsc{filename must be your full name!} \end{enumerate} \begin{center} \begin{tikzpicture} % Button background \node[draw, rounded corners=8pt, fill=blue!30, inner sep=10pt] (button) {\textbf{Submit}}; % Text label % Define the URL \def\myurl{https://abaj.io/bday/problems/upload} % Add a link \node[anchor=center] (link) at (button.center) {\href{\myurl}{\phantom{Submit}}}; \end{tikzpicture} \end{center} \hrulefill \section*{Problems} \begin{questions} \question[2] \[\int_0^3 \sqrt{9-x^2}\, \mathrm{d}x\] \begin{solutionordottedlines}[2cm] \end{solutionordottedlines} \question[2] \[2\iiint\limits_{V} \,\mathrm{d}V, V : \{(r, \theta, \phi) \,|\, 0 \leq r \leq 1,\, 0 \leq \theta \leq 2\pi,\, 0\leq \phi \leq \pi\}\] \begin{solutionordottedlines}[1in] \end{solutionordottedlines} \question[3] \[\int \frac{\cos{x}}{3+2\cos{x}} \, \mathrm{d}x\] \begin{solutionordottedlines}[1in] \end{solutionordottedlines} \question[2] Precisely mark out $\sqrt{2}$ on a number line. \begin{solutionorbox}[1in] \end{solutionorbox} \question[2] What is the exact value of $(\frac{3}{2})!$ \begin{solutionordottedlines}[1in] \end{solutionordottedlines} \question[3] Prove the Pythagorean Theorem. \begin{solutionordottedlines}[1.5in] \end{solutionordottedlines} \question[4] Find the derivative of $\sin{x}$ using first principles. State any and all lemmas. \begin{solutionordottedlines}[2in] \end{solutionordottedlines} \question \begin{parts} \part[1] List the first 10 terms of the Fibonacci sequence. \begin{solutionordottedlines}[0.5in] \end{solutionordottedlines} \part[2] Explain how this sequence is present in the \textbf{Mandelbrot Set}. \begin{solutionordottedlines}[1in] \end{solutionordottedlines} \end{parts} \question[3] \[\int^\infty_\infty \mathrm{e}^{-x^2} \,\mathrm{d}x\] \begin{solutionordottedlines}[1.5in] \end{solutionordottedlines} \question[2] What does the sum $1 - \frac{1}{3} + \frac{1}{5} - \frac{1}{7} + \frac{1}{9} - ...$ converge to? \begin{solutionordottedlines}[1in] $\frac{\pi}{4}$ \end{solutionordottedlines} \question[1] Calculus is for \fillin[children] whilst analysis is for \fillin[adults]. \question[2] What is the angle between the two curves $f(x) = x^4 -5x^3$ and $g(x) = 8x-40$ at either of their points of intersection? \begin{solutionordottedlines}[1in] \end{solutionordottedlines} \question[2] What is the shortest path you can take from node $s$ to node $t$ in figure 1? \begin{solutionordottedlines}[1in] \end{solutionordottedlines} \question[2] What are the \textbf{complex} solutions to $\sin(z) = 2$? \begin{solutionordottedlines}[1in] \end{solutionordottedlines} \question \begin{parts} \part[4] Find a closed form for the recurrence $T(n) = T(n-1) + T(n-2)$, with initial conditions $T(0) = 0$ and $T(1) = 1$. \begin{solutionordottedlines}[1in] \[T(n) = \frac{\varphi^n-(1-\varphi)^n}{\sqrt{5}}\] \end{solutionordottedlines} \part[1] Hence find $T(27)$. \end{parts} \begin{solutionordottedlines}[1in] $196,418$ \end{solutionordottedlines} \question[2] Solve the following differential equation $y'' + 2y' + y = e^{-x}\cos(x)$ with initial value conditions of $y = 0$ and $y' = 1$. \begin{solutionordottedlines}[1in] $y(x) = (x-\cos(x)+1)e^{-x}$ \end{solutionordottedlines} \question[2] What is the dot product of the functions $\sin(x)$ and $\cos(x)$Linear question. \begin{solutionordottedlines}[1in] $0$ \end{solutionordottedlines} \question[3] How many permutations of the Rubiks cube exist? Give your answer as an expression. \begin{solutionordottedlines}[1in] $8! \times 3^7 \times 12! \times 2^{11} = 43,252,003,274,489,856,000$ \end{solutionordottedlines} \question[2] Decode using the Caesar cipher: \textit{Urqh zdv qrw exlow lq d gdb}. \begin{solutionordottedlines}[1in] Rome was not built in a day. \end{solutionordottedlines} \question[2] Calculate the length of the curve from $0$ to $4$ for $f(x) = x^2$. \begin{solutionordottedlines}[1in] \end{solutionordottedlines} \question[2] Negate the following statement and reexpress it as an equivalent positive one. \textsc{Everyone who is majoring in math has a friend who needs help with his or her homework.} \begin{solutionordottedlines}[1in] There is at least one math major who has no friends needing help with their homework. \end{solutionordottedlines} \question[2] Let the Dirichlet function be defined as: \[ \Dirichlet(x) = \begin{cases} 1 & \text{if } x \text{ is rational}, \\ 0 & \text{if } x \text{ is irrational}. \end{cases} \] Thus evaluate \(\int_0^1 D(x), \mathrm{d}x\). \begin{solutionordottedlines}[1in] $0$ \end{solutionordottedlines} \end{questions} \newpage \section*{Diagrams} \begin{multicols}{3} \begin{minipage}{\linewidth} \begin{tikzpicture}[scale=0.65,transform shape] % Nodes \Vertex[x=0,y=0, L={$s$}]{s} \Vertex[x=2,y=2, L={$v_1$}]{v1} \Vertex[x=2,y=-2, L={$v_2$}]{v2} \Vertex[x=5,y=2, L={$v_3$}]{v3} \Vertex[x=5,y=-2, L={$v_4$}]{v4} \Vertex[x=7,y=0, L={$t$}]{t} % Edges \tikzset{EdgeStyle/.append style = {->, >=Latex, line width=1pt}} \Edge[label=16](s)(v1) \Edge[label=13](s)(v2) \Edge[label=12](v1)(v3) \Edge[label=9](v2)(v3) \Edge[label=14](v2)(v4) \Edge[label=7](v3)(v4) \Edge[label=20](v3)(t) \Edge[label=4](v4)(t) \tikzset{EdgeStyle/.append style = {bend left = 15}} \Edge[label=4](v1)(v2) \Edge[label=10](v2)(v1) \end{tikzpicture} \captionof*{figure}{} \end{minipage} \begin{minipage}{\linewidth} \begin{tikzpicture}[scale=0.6, transform shape] \begin{axis}[ axis lines = left, xlabel = \( x \), ylabel = {\( y \)}, ylabel style={rotate=-90}, ] % Plot the function y = x^2 \addplot [ domain=-1:5, samples=100, color=red, ] {x^2}; % Highlight the section from 0 to 4 in blue \addplot [ domain=0:4, samples=100, color=blue, thick, ] {x^2}; \end{axis} \end{tikzpicture} \end{minipage} \begin{minipage}{\linewidth} \begin{tikzpicture}[scale=0.7] \begin{axis}[ axis lines=middle, xmin=0, xmax=1, ymin=0, ymax=1.5, xlabel=$x$, ylabel=$f(x)$, ytick={0, 1}, yticklabels={0, 1}, small ] % Define a fixed non-zero denominator for rational numbers \def\denominator{10} % Plot rational points \foreach \p in {1,...,100}{ \pgfmathsetmacro{\rational}{mod(\p/\denominator, 1)} \addplot[only marks, mark=*, mark options={scale=0.3}, color=blue] coordinates {(\rational, 1)}; } % Plot irrational points \foreach \i in {1,...,100}{ \pgfmathsetmacro{\irrational}{mod(\i*sqrt(2), 1)} \addplot[only marks, mark=*, mark options={scale=0.3}, color=red] coordinates {(\irrational, 0)}; } \end{axis} \end{tikzpicture} \end{minipage} \end{multicols} \section*{Marking} \multirowgradetable{2}[questions] \end{document}