you must start with plot
subplot(3,5,1);
plot(t, a);
title('Agent-1 Error of Target-1')
ylabel('X Dimension Error');
xlabel('Time');
subplot(3,5,6);
plot(t, b);
ylabel('Y Dimension Error');
xlabel('Time');
subplot(3,5,11);
plot(t, c);
ylabel('Z Dimension Error');
xlabel('Time');
