Skip to main content \(\require{cancel}\newcommand{\definiteintegral}[4]{\int_{#1}^{#2}\,#3\,d#4}
\newcommand{\myequation}[2]{#1\amp =#2}
\newcommand{\indefiniteintegral}[2]{\int#1\,d#2}
\newcommand{\testingescapedpercent}{ \% }
\newcommand{\bvec}{{\mathbf b}}
\newcommand{\vvec}{{\mathbf v}}
\newcommand{\class}[2][\sim]{\lbrack #2\rbrack_{#1}}
\newcommand{\lt}{<}
\newcommand{\gt}{>}
\newcommand{\amp}{&}
\definecolor{fillinmathshade}{gray}{0.9}
\newcommand{\fillinmath}[1]{\mathchoice{\colorbox{fillinmathshade}{$\displaystyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\textstyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\scriptstyle \phantom{\,#1\,}$}}{\colorbox{fillinmathshade}{$\scriptscriptstyle\phantom{\,#1\,}$}}}
\newcommand{\sfrac}[2]{{#1}/{#2}}
\)
Instructions.
Let
\(\vec{x}\) be represented by the red arrow, and
\(A\vec{x}\) by the grey arrow, for some particular
\(2\times 2\) matrix
\(A\text{.}\) Drag the
tip of the red arrow to see the grey arrow change.
