3 \subsection{Direct definition}
5 The object \Lkeyword{vecteur} allows us to define and draw a \Index{vector}.
6 To do so in a simple way, we use the option \Lkeyword{args} to define
7 its components $(x,y)$ and we specify the point from where the
8 vector starts with the macro \Lcs{psProjection} (or we may use a
11 As with points, we can save the components of a vector using the
12 option \Lkeyword{name}.
14 \begin{LTXexample}[width=7.5cm]
15 \begin{pspicture}(-3,-3)(4,3.5)%
16 \psframe*[linecolor=blue!50](-3,-3)(4,3.5)
17 \psset{viewpoint=50 30 15,Decran=60}
19 %% definition du plan de projection
26 %% definition du point A
27 \psProjection[object=point,
31 \psProjection[object=vecteur,
35 \psProjection[object=vecteur,
39 \axesIIID(4,2,2)(5,4,3)
44 \subsection{Some more definitions}
46 There are other methods to define a vector in 2D. The options
47 \Lkeyword{definition} and \Lkeyword{args} allow us a variety of supported
52 \item \texttt{\Lkeyword{definition}=\Lkeyval{vecteur}};
53 \texttt{\Lkeyword{args}=$A$ $B$}.
55 The vector $\overrightarrow {AB}$
57 \item \texttt{\Lkeyword{definition}=\Lkeyval{orthovecteur}};
58 \texttt{\Lkeyword{args}=$u$}.
60 A vector perpendicular to $\vec u$ with the same length.
62 \item \texttt{\Lkeyword{definition}=\Lkeyval{normalize}};
63 \texttt{\Lkeyword{args}=$u$}.
65 The vector $\Vert \vec u \Vert ^{-1} \vec u$
66 if $\vec u \neq \vec 0$, and $\vec 0$ otherwise.
68 \item \texttt{\Lkeyword{definition}=\Lkeyval{addv}};
69 \texttt{\Lkeyword{args}=$u$ $v$}.
71 The vector $\vec u + \vec v$
73 \item \texttt{\Lkeyword{definition}=\Lkeyval{subv}};
74 \texttt{\Lkeyword{args}=$u$ $v$}.
76 The vector $\vec u - \vec v$
78 \item \texttt{\Lkeyword{definition}=\Lkeyval{mulv}};
79 \texttt{\Lkeyword{args}=$u$ $\alpha $}.
81 The vector $\alpha \vec u$