disp('question 1)a)')
v=[1000:-1:0]';
printf('\n v(3) vaut %g\n',n,r)F

disp('question 1)b)')
P=poly([-4 0 1],'X','c')F

disp('question 1)c)')
disp('voir la figure')
x=[-1:.1:1]; y=x; z=x'*y; plot3d(x,y,z);