1*1 + 1*-1 = 0
axis([-3 3 0 6]) ; axis square
Pl4 = [0 0 1 0 0; 0 0 0 0 0; 0 0 0 0 1; 0 1 0 0 0; 0 0 0 0 0]
Pr4 = [0 0 0 0 1; 1 0 0 0 0; 0 0 0 0 0; 0 0 0 1 0; 0 0 0 0 0 ]
M= [6 -6 4]'
en = [0 0.6 0.8]
T1 = [1 0 -10; 0 1 -2;0 0 1]; T2 = [0 -1 0; 1 0 0 ; 0 0 1]; T3 = [1 0 10; 0 1 2;0 0 1]; TT = T3*T2*T1 % =[0 -1 12; 1 0 -8 ; 0 0 1]; Q = [10 20 20 10 10; -8 -8 2 2 -8; 1 1 1 1 1]; QT = TT*Q; plot(Q(1,:),Q(2,:)); hold on; plot(QT(1,:),QT(2,:),'r'); axis([-22 22 -22 22]); axis square; hold off
w=(0:0.02:5)*2*pi; z= 6*cos(w); x= 6*sin(w); yr= w*1.2/2/pi; yl = -yr; clf; plot3(x,yr,z); hold on; plot3(x,yl,z,'m'); axis equal; hold off