Skip to main content\(\require{cancel}\newcommand{\nicefrac}[2]{{{}^{#1}}\!/\!{{}_{#2}}}
\newcommand{\unitfrac}[3][\!\!]{#1 \,\, {{}^{#2}}\!/\!{{}_{#3}}}
\newcommand{\unit}[2][\!\!]{#1 \,\, #2}
\newcommand{\noalign}[1]{}
\newcommand{\qed}{\qquad \Box}
\newcommand{\mybxbg}[1]{\boxed{#1}}
\newcommand{\mybxsm}[1]{\boxed{#1}}
\newcommand{\allowbreak}{}
\newcommand{\lt}{<}
\newcommand{\gt}{>}
\newcommand{\amp}{&}
\definecolor{fillinmathshade}{gray}{0.9}
\newcommand{\fillinmath}[1]{\mathchoice{\colorbox{fillinmathshade}{$\displaystyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\textstyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\scriptstyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\scriptscriptstyle\phantom{\,#1\,}$}}}
\)
Chapter 4 Fourier series and PDEs
For a higher quality printout use the PDF version: https://www.jirka.org/diffyqs/diffyqs.pdf