\input $HOME/tex_doc/format/myplain.tex \let \exo \Exo \magnification 1200 \date {20 janvier 2003} \classe {s1 mai} \duree {1h} \withoutcorrigbody \titre {\twentybf Devoir surveillé n\raise 5pt \hbox {\tenbf o} 4} \def \datapath {% $HOME/tex_doc/lycee/database/btsmai/analyse/equadiff/} \bareme {20} \input \datapath equ2_017.tex \bye