-------------------------------------------------------------------- I - Matrices magiques -------------------------------------------------------------------- b=magic(5) b = 17 24 1 8 15 23 5 7 14 16 4 6 13 20 22 10 12 19 21 3 11 18 25 2 9 sum(b) ans = 65 65 65 65 65 sum(b') ans = 65 65 65 65 65 sum(diag(b)) ans = 65 sum(diag(fliplr(b))) ans = 65 b(3,1:5) ou b(3,:) ans = 4 6 13 20 22 b(1,2) ans = 24 -------------------------------------------------------------------- II - Expression -------------------------------------------------------------------- a=3 a = 3 >> b=-1 b = -1 >> c=-7 c = -7 >> D=b^2-4*a*c D = -21 >> x1=(-b-sqrt(D))/(2*a) x1 = -1.3699 >> x2=(-b+sqrt(D))/(2*a) x2 = 1.7033 -------------------------------------------------------------------- III - Travailler avec les matrices -------------------------------------------------------------------- >> load matrice.dat >> matrice matrice = 1 2 3 4 5 6 7 8 9 >> X=[matrice zeros(3,3); zeros(3,3) matrice] X = 1 2 3 0 0 0 4 5 6 0 0 0 7 8 9 0 0 0 0 0 0 1 2 3 0 0 0 4 5 6 0 0 0 7 8 9 >> X (:,end)= [] X = 1 2 3 0 0 4 5 6 0 0 7 8 9 0 0 0 0 0 1 2 0 0 0 4 5 0 0 0 7 8 >> X (end,:)= [] X = 1 2 3 0 0 4 5 6 0 0 7 8 9 0 0 0 0 0 1 2 0 0 0 4 5 -------------------------------------------------------------------- IV - La fenêtre de commandes -------------------------------------------------------------------- >> format short e >> R = 0 >> Rot = [ cos(R) sin(R) ; -sin(R) cos(R)] Rot = 1 0 0 1 >> R = 0.5 R = 5.0000e-01 >> Rot = [ cos(R) sin(R) ; -sin(R) cos(R)] Rot = 8.7758e-01 4.7943e-01 -4.7943e-01 8.7758e-01 >> R = pi/3 R = 1.0472e+00 >> Rot = [ cos(R) sin(R) ; -sin(R) cos(R)] Rot = 5.0000e-01 8.6603e-01 -8.6603e-01 5.0000e-01