Tracé d’une courbe paramétrée à partir de points particuliers

Auteur ou autrice : Maxime Chupin.

Mise en ligne le 28 novembre 2023

Code

% @Auteur: Maxime Chupin
% @date: 2011

verbatimtex 
%&latex 
\documentclass{article} 
\usepackage{amsmath}
\begin{document} 
etex 


u=3cm;
v=3;

beginfig(1);
 
    %axes
    drawarrow (-1.5u,0)--(1.5u,0) withpen pencircle scaled 0.2;
    drawarrow (0,-1.5u)--(0,1.5u) withpen pencircle scaled 0.2;
 
    %unités
    draw (-2,u)--(2,u) withpen pencircle scaled 0.2;
    draw (u,-2)--(u,2) withpen pencircle scaled 0.2;
 
    %courbe
    draw (-u,-u){1,2.25}..(-0.5u,0)..(0,0.707u)..(0.5u,1u){1,0}..(1u,0){0,-1}
	..(0.5u,-1u){-1,0}..(0,-0.707u)..(-0.5u,0)..(-1u,1u){-1,2.25} 
	withcolor (0.18,0.55,0.34);
 
    %tangentes
    drawarrow (-u,-u)--(-0.9u,-0.775u)  withcolor red;
    drawarrow (0.5u,1u)--(0.8u,1u)  withcolor red;
    drawarrow (1u,0)--(1u,-0.3u)  withcolor red;
    drawarrow (0.5u,-1u)--(0.2u,-1u)  withcolor red;
 
 
    %labels
    label.lrt(btex $x$ etex,(1.3u,0));
    label.lrt(btex $y$ etex,(0,1.4u));
    label.rt(btex $1$ etex,(0,u));
    label.llft(btex $1$ etex,(u,0));
 
    label.lrt(btex $\begin{cases}x=\cos 2t\\[2mm]y=\sin 3t\end{cases}$ etex,(-0.8u,-0.8u));
 
endfig;
end