Help needed: empty plot when plotting for loop

Hello,

Below is my code. I am trying to plot all values of the for loop but I am getting an empty plot. What am I doing incorrectly?

for i=2:1:1369
    a = (V(i+1)-V(i-1))/(2*(t(i+1)-t(i-1)));

A = ((1/2)*Rhoa*Cd*Af*(V(i).^3));
G = (Mv*g*cos(0).*V(i));
I = (1.1*Mv.*a.*V(i));

Pw = (A+G+I)/1000;

end


figure
hold on
i=2:1:1369;
plot(i,Pw); 
grid
xlabel('Time (s)')
ylabel('Power, Pw (KW)')
set(h,'linewidth',2)

Answer 1

[Walter Roberson]

Do not assign to Pw. Instead assign to Pw(i-1)

[JD]

That worked!! Thank you so much!!

[JD]

Hi Walter,

After being able to plot the graph based on your response to this question, I realized my for loop is not doing what I want. Would you be able to help with the below question as well?

Thanks

https://www.mathworks.com/matlabcentral/answers/480854-how-to-reference-a-variable-saved-as-mat-file-to-execute-code