#LyX 1.5.1 created this file. For more info see http://www.lyx.org/ \lyxformat 276 \begin_document \begin_header \textclass amsart \language english \inputencoding auto \font_roman default \font_sans default \font_typewriter default \font_default_family default \font_sc false \font_osf false \font_sf_scale 100 \font_tt_scale 100 \graphics default \paperfontsize default \spacing double \papersize default \use_geometry false \use_amsmath 1 \use_esint 1 \cite_engine basic \use_bibtopic false \paperorientation portrait \leftmargin 1.2in \topmargin 1.2in \rightmargin 1.2in \bottommargin 1.2in \secnumdepth 3 \tocdepth 3 \paragraph_separation indent \defskip medskip \quotes_language english \papercolumns 1 \papersides 1 \paperpagestyle default \tracking_changes false \output_changes false \author "" \author "" \end_header \begin_body \begin_layout Title Math Review #2 Supplement (Math Camp 2007) \end_layout \begin_layout Author John Morrow \end_layout \begin_layout Date 8/23/07 \end_layout \begin_layout Standard What follows is a rough sketch of material for Day 2 and a few more problems. \end_layout \begin_layout Section Day 2 \end_layout \begin_layout Enumerate Functions \end_layout \begin_deeper \begin_layout Enumerate Example: \begin_inset Formula $\mathbb{R}^{1}\rightarrow\mathbb{R}^{1}$ \end_inset \end_layout \begin_layout Enumerate Monotone functions. \end_layout \begin_layout Enumerate \series bold Problem: \series default Construct examples on \begin_inset Formula $[0,1]$ \end_inset of the following types of functions and find the points in \begin_inset Formula $[0,1]$ \end_inset where they are maximized and minimized: \end_layout \begin_deeper \begin_layout Enumerate Strictly increasing. \end_layout \begin_layout Enumerate Strictly decreasing. \end_layout \begin_layout Enumerate Increasing but not strictly increasing. \end_layout \begin_layout Enumerate A function which fails both definitions of increasing and decreasing functions. \end_layout \end_deeper \begin_layout Enumerate Example: \begin_inset Formula $\mathbb{R}^{2}\rightarrow\mathbb{R}^{2}$ \end_inset \end_layout \begin_layout Enumerate Example: \begin_inset Formula $\mathbb{R}^{N}\rightarrow\mathbb{R}^{1}$ \end_inset \end_layout \begin_layout Enumerate Concave/Convex functions. \end_layout \end_deeper \begin_layout Enumerate Smoothness \end_layout \begin_deeper \begin_layout Enumerate Sequences. \end_layout \begin_layout Enumerate Open/closed intervals. \end_layout \begin_layout Enumerate Closed and bounded intervals, convergence of sequences. \end_layout \begin_layout Enumerate \series bold Problem: \series default Suppose for a given sequence \begin_inset Formula $\{a_{n}\}$ \end_inset that \begin_inset Formula $|a_{n}|\leq M$ \end_inset for some constant \begin_inset Formula $M$ \end_inset . Show that \begin_inset Formula $\{a_{n}\}$ \end_inset has a convergent subsequence. Does \begin_inset Formula $\{a_{n}\}$ \end_inset have to converge to a unique number \begin_inset Formula $a$ \end_inset ? (Prove or provide a counterexample.) \end_layout \begin_layout Enumerate Continuity. \end_layout \begin_layout Enumerate Continuous functions on closed and bounded sets always take on maximal and minimal values. \end_layout \begin_layout Enumerate \series bold Problem: \series default \begin_inset Formula $f(x)\equiv1/|x|$ \end_inset fails to take on a maximal value. How does this fail to happen? \end_layout \begin_layout Enumerate The derivative on \begin_inset Formula $\mathbb{R}^{1}$ \end_inset . \end_layout \begin_layout Enumerate \series bold Problem: \series default Show that continuity of \begin_inset Formula $f(x)$ \end_inset at \begin_inset Formula $y$ \end_inset is a necessary condition for \begin_inset Formula $f$ \end_inset to be differentiable at \begin_inset Formula $y$ \end_inset . \end_layout \begin_layout Enumerate \begin_inset Formula $\mathcal{C}^{1}$ \end_inset , \begin_inset Formula $\mathcal{C}^{2}$ \end_inset , \begin_inset Formula $\mathcal{C}^{\infty}$ \end_inset . \end_layout \end_deeper \begin_layout Enumerate Optimization Primer \end_layout \begin_deeper \begin_layout Enumerate Local/Global Maxima and Minima. \end_layout \begin_layout Enumerate Uniqueness of maxima/minima for strictly concave/convex functions. \end_layout \begin_layout Enumerate \series bold Problem: \series default Provide an example of a function which is concave and convex. \end_layout \begin_layout Enumerate Necessity of critical points for maxima/minima. \end_layout \begin_layout Enumerate \series bold Problem: \series default Construction a function \begin_inset Formula $f(x)$ \end_inset where for some \begin_inset Formula $y$ \end_inset we have \begin_inset Formula $f'(y)=0$ \end_inset but \begin_inset Formula $f'(y)$ \end_inset is not a local max or min. \end_layout \begin_layout Enumerate Critical points sufficient for maxima/minima under concavity/convexity. \end_layout \end_body \end_document