How do i resolve this error message?

I keep getting this error can anyone help?

Array indices must be positive integers or logical values.

Error in Assignment_3_Question_2 (line 24)

m(i)=5000*dt - m(t-dt);

Here is the code:

clear

dm=5000;
dt=1;
t=0:dt:1000;
Ve=4500;
G=6.67408e-11;
M=5.9722e24;
R=6371;
A=75;
Cd=0.4;
p=zeros(1,length(t));
m=zeros(1,length(t));
V=zeros(1,length(t));
h=zeros(1,length(t));
p(1)=1.225;
m(1)=894000;
m_final=54000;
V(1)=0;
h(1)=0;

for i=1:length(t)
    if m(i)~=m_final
        m(i)=5000*dt - m(t-dt);
    else
        m(i)=-m(t-dt);
    end
    p(i)=1.225*e(-3*h(i)/50000);
    h(i)=h(t-dt)+((dt(V(t)+V(t-dt))))/2;
    V(i)=Ve-((Ve*m(t))/m(t-dt))-((dt*G*M)/(R+h(t-dt)).^2)-((dt*p(h(t-dt)))*A*Cd*(V(t-dt)).^2)/2*(m(t-dt))+V(t-dt);
end

plot(t,V,'or')
xlabel('Time(s)')
ylabel('Velocity(m/s)')

[KSSV]

Problem with indexing in time.

Answer 1

[Star Strider]

I cannot determine what you want to do in this assignment:

m(i)=5000*dt - m(t-dt);

or this one:

m(i)=-m(t-dt);

since those appears to be throwing the error.

Perhaps:

m(i)=5000*dt - m(i)*(t(i)-dt);

or something similar in the other one as well will do what you want.

.