\documentclass[a4paper,12pt]{article}
\newcommand{\un}{\underline}
\usepackage{epsfig}
\begin{document}
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\begin{center}
\textbf{Vector Functions and Curves}

\textit{\textbf{One variable functions}}
\end{center}

\textbf{Question}

Find the velocity, speed and acceleration of the particle with
position given by $\un{r}(t)$ at time
$t$. Also determine the particles path.

$$\underline{r}=\underline{i}+t\underline{j}+t\underline{k}$$


\textbf{Answer}

Position: $\underline{r}=\underline{i}+t\underline{j}+t\underline{k}$

Velocity: $\underline{v}=\underline{j}+\underline{k}$

Speed: $\it{v}=\sqrt{2}$

Acceleration: $\underline{a}=\underline{0}$

Path: the straight line $x=1$, $y=z$.


\end{document}