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\title{A Simple Guide to the TI-92 Graphing Calculator}
\author{For Beginners}
\date{}

\begin{document}

\maketitle

\section{Introduction}
The TI-92 is a powerful graphing calculator with built-in programs for math, graphing, and more. This guide covers basic navigation, a sample program, and an example of 3D graphing to get started.

\section{Navigating Programs}
The TI-92 organizes functions into apps (like Home, Graph, etc.). Use the \textbf{APPS} key to access them.

\begin{multicols}{2}

\subsection{Key Navigation}
\begin{itemize}[leftmargin=*]
\item \textbf{APPS}: Opens the Apps desktop.
\item Arrow keys: Navigate menus and lists.
\item \textbf{ENTER}: Selects an item.
\item \textbf{2nd} + \textbf{F1--F8}: Accesses secondary functions (e.g., \textbf{2nd} + \textbf{F1} = QUIT).
\item \textbf{ALPHA}: Types letters for variables/names.
\item \textbf{CLEAR}: Clears the screen or cancels.
\item \textbf{+} (or -): Scrolls up/down in lists.
\end{itemize}

\subsection{Main Apps}
\begin{longtable}{ll}
\toprule
App & Description \\
\midrule
Home & Basic calculations and programming. \\
Graph & Plot functions and analyze graphs. \\
Data/Matrix & Work with lists, matrices, and stats. \\
Symbolic & Exact symbolic math (solve, factor). \\
Spreadsheet & Data entry and formulas. \\
\bottomrule
\end{longtable}

\subsection{Accessing Programs}
\begin{enumerate}[leftmargin=*]
\item Press \textbf{APPS}.
\item Use arrows to select an app (e.g., Home).
\item Press \textbf{ENTER}.
\item In Home, press \textbf{F3} (PROGRAMS) for user programs.
\item Select \textbf{New} to create, or existing to run.
\end{enumerate}

\subsection{Running a Program}
\begin{itemize}[leftmargin=*]
\item In PROGRAMS menu: Arrows to program name.
\item Press \textbf{ENTER} to execute.
\item Input prompts appear; type values and press \textbf{ENTER}.
\end{itemize}

\end{multicols}

\newpage

\section{Sample Program: Hello Looper}
This program accepts a name and a number, then loops to display "Hello, [name]!" that many times. Save it in Home > PROGRAMS > New.

\begin{lstlisting}[caption={Hello Looper Program}, label={lst:hello}]
:Prgm
:Input "Enter your name: ",name
:Input "Enter loop times: ",times
:For i,1,times
:Disp "Hello, "&name&"!"
:EndFor
:EndPrgm
\end{lstlisting}

\subsection{How to Use the Sample}
\begin{enumerate}[leftmargin=*]
\item Create: In PROGRAMS, name it "HELLOOP".
\item Run: Select HELLOOP and press \textbf{ENTER}.
\item Enter name and number when prompted.
\item View the looped greetings on screen.
\end{enumerate}

\subsection{Tips for Youth}
\begin{itemize}[leftmargin=*]
\item Experiment: Change the message or add pauses.
\item Errors? Press \textbf{CLEAR} and retry.
\item Save often: Programs are stored in memory.
\end{itemize}

\section{Using the 3D Graphing Function}
The TI-92 can plot 3D graphs in the Graph app. Below is an example using the equation $z = \sin(\sqrt{x^2 + y^2})$ to create a ripple-like surface.

\subsection{Steps to Graph in 3D}
\begin{enumerate}[leftmargin=*]
\item Press \textbf{APPS}, select \textbf{Graph}, press \textbf{ENTER}.
\item Press \textbf{F1} (Y= editor), select \textbf{3D}.
\item Enter the equation: $z1=\sin(\sqrt{x^2+y^2})$.
\item Press \textbf{F2} (WINDOW) to set ranges:
  \begin{itemize}[leftmargin=*]
  \item $x$: [-5, 5], $y$: [-5, 5], $z$: [-2, 2].
  \item Grid: 20 for $x$ and $y$.
  \end{itemize}
\item Press \textbf{F5} (GRAPH) to plot.
\item Use arrow keys to rotate, \textbf{+} or \textbf{-} to zoom.
\end{enumerate}

\subsection{Why This Equation?}
The equation $z = \sin(\sqrt{x^2 + y^2})$ creates a 3D wave pattern, symmetric around the origin, making it visually engaging and easy to explore.

\end{document}