My figures are not plotting any data, I tried changing the number of points and step size multiple times but it didn't change

% THE PROJECT

%

clear

%

N=100 %number of points

h=0.1 % step size

ts=20 %starting time

%^

for i=1:N

t1(i)=exp(-2*ts)*sin(pi*ts);

F(i)=-exp(-2*t1(i))*(2*sin(pi*t1(i))-pi*cos(pi*t1(i))); %position

Fv(i)=-exp(-2*t1(i))*((pi^(2)-4)*sin(pi*t1(i))+4*pi*cos(pi*t1(i))); %velocity

Fa(i)=-exp(-2*t1(i))*((6*pi^(2)-8)*sin(pi*t1(i))+(12*pi-pi^(3)*cos(pi*t1(i)))); %acceleration

end

%

for i=1:N

if(i<=2) %forward

Fd(i)=(-F(i+2)+4*F(i+1)-3*F(i))/(2*h);

Fdd(i)=(-F(i+3)+4*F(i+2)-5*F(i+1)+2*F(i))/(h^2);

elseif ((i==N) | (i==N-1)) %backwards

Fd(i)=(3*F(i)-4*F(i-1)+F(i-2))/(2*h);

Fdd(i)=(2*F(i)-5*F(i-1)+4*F(i-2)-F(i-3))/(h^2);

else %center

Fd(i)=(-F(i+2)+8*F(i+1)-8*F(i-1)+F(i-2))/(12*h);

Fdd(i)=(-F(i+2)+16*F(i+1)-30*F(i)+16*F(i-1)-F(i-2))/(12*h^2)

end

end

%

%

figure (1)

plot(t1,F)

title('Rocket position')

xlabel('time(s)')

ylabel('position(m)')

%

figure(2)

plot(t1,Fv,t1,Fd)

title('Rocket velocity')

xlabel('time(s)')

ylabel('velocity(m/2)')

%

figure(3)

plot(t1,Fa,t1,Fdd)

title('Rocket acceleration')

xlabel('time(s)')

ylabel('acceleration(m/s^2)')

%

figure(4)

plot(t1,(Fv-Fd),t1,(Fa-Fdd))

legend('Vel error','Acc Err')

%

figure(5)

subplot(2,2,1),plot(t1,F)

title('Rocket position')

xlabel('time(s)')

ylabel('position(m)')

%

subplot(2,2,2),plot(t1,Fv,t1,Fd)

title('Rocket velocity')

xlabel('time(s)')

ylabel('velocity(m/2)')

%

subplot(2,2,3),plot(t1,Fa,t1,Fdd)

title('Rocket acceleration')

xlabel('time(s)')

ylabel('acceleration(m/s^2)')

%

subplot(2,2,4),

plot(t1,(Fv-Fd),t1,(Fa-Fdd))

legend('Vel error','Acc Err')

Answer 1

[Jason Shrand]

They actually are being plotted, but you aren't seeing anything because every point in your data set is the same constant value.

For example, in the for loop at the top of the script, you have:

t1(i)=exp(-2*ts)*sin(pi*ts);

This value is always constant. I think what you need is something like

t1(i)=exp(-2*ts)*sin(pi*ts)*i;