Matrices, vectors, and miscellaneous

This table describes how to type matrices, vectors, and other miscellaneous expressions, along with usage examples (including the typeset equivalent.) If the expression you need is not listed, please define your own and explain the meaning of your notation.

Expression	Description	Examples
[A B C] [D E F] [G H I]	A matrix. Enclose each row within [ ].	$\left[ \begin{array}{ccc} 2 & 1 & 0 \\ 4 & 7 & 3 \\ 2 & 0 & 1 \end{array} \right]$ [2 1 0] [4 7 3] [2 0 1]
->PQ	A vector, with initial point P and terminal point Q.	$\overset{\rightharpoonup}{PQ}$ ->PQ
u = <x,y> v = <x,y>	Vectors u and v in component form. Component form is defined with initial point at the origin, and terminal point (x,y).	$\mathbf{v}=\langle -5,12 \rangle$ v = <-5,12>
||v||	The norm, or length, of vector v. If $\mathbf{v}=\langle v_1,v_2 \rangle, \; \left\lVert\mathbf{v} \right\rVert =\sqrt{v_{1}^{\phantom{1}2}+v_{2}^{\phantom{1}2}}$	If $\mathbf{v}=\langle -5,12 \rangle,\;\left\lVert\mathbf{v} \right\rVert =13$ If v = <-5,12>, ||v|| = 13
u dot v or u . v	Dot product. Only use u . v if there can be no ambiguity with a period or decimal point.	$\mathbf{u\cdot v }$ u dot v u . v
u cross v or u x v	Cross product. Only use u x v if there can be no ambiguity with the letter x or the ordinary multiplication operator.	$\mathbf{u\times v }$ u cross v u x v
oo, -oo	Positive infinity, negative infinity	$$\lim_{x \to -\infty} x^2=\infty$$ lim x->-oo x^2 = oo