%13 October 1998, Russell Brown \documentclass[12pt]{article} \input{rmb_local} \input{rmb_macros} \pagestyle{empty} \oddsidemargin -0.25in \textwidth 6.5in \textheight 9in \topmargin -.5in \begin{document} \begin{flushleft} \course \hfill Russell Brown \\ Review 2 \hfill \today The second hour exam is on Tuesday, 20 October from 7:30pm--9:30pm in CB 114. You may use a graphing calculator on the exam. You may not use notes, textbooks, a computer or a calculator with symbolic manipulation capabilities such as a TI-92. Below are a selection of problems to help you prepare for the exam. You should also review material covered in lecture and the problems assigned for recitation. \begin{enumerate} \item Estimate the following limits. Your answers should be correct to 2 decimal places. $$ \lim _{x\rightarrow 0} \sin (e^x-1)/ x , \qquad \lim _{x\rightarrow 0} \frac {2^x-3^x} x . $$ \item Find the following limits using the limit laws, if they exist. Explain each step of your solution. If a limit does not exist, determine if it $\infty$ or $-\infty$. $$ \lim_{x\rightarrow 2} \frac {x-2} {x^2-4}, \qquad \lim _{x\rightarrow 2} \frac {x+2} {x^2+4}, \qquad \lim_{x\rightarrow 2} \frac {x+3}{x-2}. $$ \item Find the following limits, if they exist. If the limit does not exist, explain why. $$ \lim _{x\rightarrow 0} \frac {|x|} x, \qquad \lim _{x\rightarrow \infty} \frac { x^2 + 3} { 3x^2+4x}. $$ \item Use the squeeze theorem to evaluate the following limits. $ \lim_{x\rightarrow \infty} \frac {\sin x } x$, $ \lim _{x\rightarrow 0} x \sin (1/x)$. \item Let $f(x)= 2^x$. Using the definition, estimate the derivative at $x=2$. \item Let $f(x) = \sqrt {2x} $. Find the derivative, $f'(x)$, using the definition. Give the domain of the derivative. \item State the definition of the derivative of $f$ at $a$. \item If $f$ is differentiable at $a$, is $f$ continuous at $a$? If your answer is yes, provide a proof. If your answer is no, provide an example. \item If $f$ is continuous at $a$, is $f$ differentiable at $a$? If your answer is yes, provide a proof. If your answer is no, provide an example. \item On which intervals are the following functions continuous? On which intervals are the functions differentiable. $$ f(x) = |x|, \qquad g(x) = \frac 1 {x^2-4}. $$ \item Show that the equation $\cos x = x$ has a solution. \item Let $f(x) = e^{2x}$. a) Estimate $f'(0)$. Explain how you arrived at your answer. b) Use the tangent line at $0$ to approximate $e^{1.02} $ and $ e^{0.99}$. \item If the prevailing price for milk is $p$ dollars per gallon, then a store will sell $Q(p)$ gallons of milk. a) What are the units for $Q'(p)$? b) Do you expect $Q'(p) >0$ or $Q'(p) < 0 $? Why? \item State the intermediate value theorem. \item Draw the graph of a function which is defined, but not continuous, at $x=2$ and which is continuous, but not differentiable, at $x=4$. \item Below are the graphs of $f$, $f'$ and $f''$. Which is which? Explain your answer. \vspace{2 in} \item Below is the graph of a function $f$. Sketch the graph of $f'$. \vspace{2 in} \item Below is the graph of a function $f'$. Sketch two possibilities for the graph of $f$. \vspace{2 in} \end{enumerate} \end{flushleft} \end{document}