Skip to main content Contents Index Prev Up Next \(\require{cancel}
\newcommand{\bigcdot}{\mathbin{\large\boldsymbol{\cdot}}}
\newcommand{\basisfont}[1]{\mathcal{#1}}
\DeclareMathOperator{\RREF}{RREF}
\DeclareMathOperator{\adj}{adj}
\DeclareMathOperator{\proj}{proj}
\DeclareMathOperator{\matrixring}{M}
\DeclareMathOperator{\poly}{P}
\DeclareMathOperator{\Span}{Span}
\DeclareMathOperator{\rank}{rank}
\DeclareMathOperator{\nullity}{nullity}
\DeclareMathOperator{\nullsp}{null}
\DeclareMathOperator{\uppermatring}{U}
\DeclareMathOperator{\trace}{trace}
\DeclareMathOperator{\dist}{dist}
\DeclareMathOperator{\negop}{neg}
\DeclareMathOperator{\Hom}{Hom}
\DeclareMathOperator{\im}{im}
\newcommand{\R}{\mathbb{R}}
\newcommand{\C}{\mathbb{C}}
\newcommand{\ci}{\mathrm{i}}
\newcommand{\cconj}[1]{\bar{#1}}
\newcommand{\lcconj}[1]{\overline{#1}}
\newcommand{\cmodulus}[1]{\left\lvert #1 \right\rvert}
\newcommand{\bbrac}[1]{\bigl(#1\bigr)}
\newcommand{\Bbrac}[1]{\Bigl(#1\Bigr)}
\newcommand{\irst}[1][1]{{#1}^{\mathrm{st}}}
\newcommand{\ond}[1][2]{{#1}^{\mathrm{nd}}}
\newcommand{\ird}[1][3]{{#1}^{\mathrm{rd}}}
\newcommand{\nth}[1][n]{{#1}^{\mathrm{th}}}
\newcommand{\leftrightlinesubstitute}{\scriptstyle \overline{\phantom{xxx}}}
\newcommand{\inv}[2][1]{{#2}^{-{#1}}}
\newcommand{\abs}[1]{\left\lvert #1 \right\rvert}
\newcommand{\degree}[1]{{#1}^\circ}
\newcommand{\iddots}{{\kern3mu\raise1mu{.}\kern3mu\raise6mu{.}\kern3mu \raise12mu{.}}}
\newcommand{\blank}{-}
\newcommand{\iso}{\simeq}
\newcommand{\abray}[1]{\overrightarrow{#1}}
\newcommand{\abctriangle}[1]{\triangle #1}
\newcommand{\mtrxvbar}{\mathord{|}}
\newcommand{\utrans}[1]{{#1}^{\mathrm{T}}}
\newcommand{\rowredarrow}{\xrightarrow[\text{reduce}]{\text{row}}}
\newcommand{\bidentmatfour}{\begin{bmatrix} 1 \amp 0 \amp 0 \amp 0 \\ 0 \amp 1 \amp 0 \amp 0 \\ 0 \amp 0 \amp 1 \amp 0
\\ 0 \amp 0 \amp 0 \amp 1\end{bmatrix}}
\newcommand{\uvec}[1]{\mathbf{#1}}
\newcommand{\zerovec}{\uvec{0}}
\newcommand{\bvec}[2]{#1\,\uvec{#2}}
\newcommand{\ivec}[1]{\bvec{#1}{i}}
\newcommand{\jvec}[1]{\bvec{#1}{j}}
\newcommand{\kvec}[1]{\bvec{#1}{k}}
\newcommand{\injkvec}[3]{\ivec{#1} - \jvec{#2} + \kvec{#3}}
\newcommand{\norm}[1]{\left\lVert #1 \right\rVert}
\newcommand{\unorm}[1]{\norm{\uvec{#1}}}
\newcommand{\dotprod}[2]{#1 \bigcdot #2}
\newcommand{\udotprod}[2]{\dotprod{\uvec{#1}}{\uvec{#2}}}
\newcommand{\crossprod}[2]{#1 \times #2}
\newcommand{\ucrossprod}[2]{\crossprod{\uvec{#1}}{\uvec{#2}}}
\newcommand{\uproj}[2]{\proj_{\uvec{#2}} \uvec{#1}}
\newcommand{\adjoint}[1]{{#1}^\ast}
\newcommand{\matrixOfplain}[2]{{\left[#1\right]}_{#2}}
\newcommand{\rmatrixOfplain}[2]{{\left(#1\right)}_{#2}}
\newcommand{\rmatrixOf}[2]{\rmatrixOfplain{#1}{\basisfont{#2}}}
\newcommand{\matrixOf}[2]{\matrixOfplain{#1}{\basisfont{#2}}}
\newcommand{\invmatrixOfplain}[2]{\inv{\left[#1\right]}_{#2}}
\newcommand{\invrmatrixOfplain}[2]{\inv{\left(#1\right)}_{#2}}
\newcommand{\invmatrixOf}[2]{\invmatrixOfplain{#1}{\basisfont{#2}}}
\newcommand{\invrmatrixOf}[2]{\invrmatrixOfplain{#1}{\basisfont{#2}}}
\newcommand{\stdmatrixOf}[1]{\left[#1\right]}
\newcommand{\ucobmtrx}[2]{P_{\basisfont{#1} \to \basisfont{#2}}}
\newcommand{\uinvcobmtrx}[2]{\inv{P}_{\basisfont{#1} \to \basisfont{#2}}}
\newcommand{\uadjcobmtrx}[2]{\adjoint{P}_{\basisfont{#1} \to \basisfont{#2}}}
\newcommand{\coordmapplain}[1]{C_{#1}}
\newcommand{\coordmap}[1]{\coordmapplain{\basisfont{#1}}}
\newcommand{\invcoordmapplain}[1]{\inv{C}_{#1}}
\newcommand{\invcoordmap}[1]{\invcoordmapplain{\basisfont{#1}}}
\newcommand{\similar}{\sim}
\newcommand{\inprod}[2]{\left\langle\, #1,\, #2 \,\right\rangle}
\newcommand{\uvecinprod}[2]{\inprod{\uvec{#1}}{\uvec{#2}}}
\newcommand{\orthogcmp}[1]{{#1}^{\perp}}
\newcommand{\vecdual}[1]{{#1}^\ast}
\newcommand{\vecddual}[1]{{#1}^{\ast\ast}}
\newcommand{\dd}[2]{\frac{d{#1}}{d#2}}
\newcommand{\ddx}[1][x]{\dd{}{#1}}
\newcommand{\ddt}[1][t]{\dd{}{#1}}
\newcommand{\dydx}{\dd{y}{x}}
\newcommand{\dxdt}{\dd{x}{t}}
\newcommand{\dydt}{\dd{y}{t}}
\newcommand{\intspace}{\;}
\newcommand{\integral}[4]{\int^{#2}_{#1} #3 \intspace d{#4}}
\newcommand{\funcdef}[3]{#1\colon #2\to #3}
\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\,}$}}}
\)
Section 1.2 Terminology and notation
linear equation
an equation of the form
\begin{equation*}
\textit{number} \text{ times } \textit{variable} \text{ plus } \textit{number} \text{ times } \textit{variable} \text{ plus } \dotsb
\text{ equals } \textit{number}
\end{equation*}
system of linear equations
a (finite) collection of linear equations
solution
a set of values that, when substituted in for the variables of a system of equations, satisfy all of the equations in the system simultaneously
solution set
the collection of all possible solutions to a system of equations
consistent system
a system of equations with at least one solution
inconsistent system
a system of equations with no solution
parametric equations
a collection of formulas, based on one or more parameters, for the variables in a linear system that represent all possible solutions to the system (as the parameters vary over all real numbers)
matrix
a rectangular array of numbers
augmented matrix
a matrix of the coefficients and constants in a linear system
matrix entry
one of the numbers in a matrix; sometimes also referred to as a matrix coefficient
row
a horizontal line of entries in a matrix
column
a vertical line of entries in a matrix
elementary row operations
the three basic operations that can be applied to an augmented matrix without changing the set of solutions to the corresponding linear system:
swap the positions of two rows,
multiply a row by a nonzero constant, and
add a multiple of one row to another.
