MATLAB: How do i dfferentiate u with respect to t

differentiation

 mi=2290000;
mf=130000;
tb=165;
t=linspace(0,165);
mr=mi-((mi-mf)*(t/tb));
hold all
g = 9.81;
Isp=263;
u=g.*(Isp.*log(mi./mr)-t);
f1=figure;
plot (t,u, 'red')
p = cumtrapz(t,u);
f2=figure; 
plot(t,p, 'blue')

Best Answer

gradient(u, t(2)-t(1))

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MATLAB: How do integrate this function over t=0 to t=165

I am not certain what you want to integrate, or what you want the final result to be.

Try this:

mi=2290000;
mf=130000;
tb=165;
t = linspace(0, tb, 150);
mr = mi-((mi-mf)*(t/tb));
mr_int = cumtrapz(t, mr);                           % Integrate ‘mr’
figure
semilogy(t,mr, 'blue')
hold on
plot(t, mr_int, 'g')
g = 9.81;
Isp=263;
u = g.*(Isp.*log(mi./mr)-t);
u_int = cumtrapz(t, u);                             % Integrate ‘u’
plot(t, u)
plot(t, u_int)
hold off
legend('mr', 'mr\_int', 'u', 'u\_int', 'Location','SE')

I ploltted the vectors in semilogy so they would all be visible.

Experiment to get different results.

MATLAB: I am trying to combine plots to one graph for u, p and a. So i need three separate graphs in total but im having trouble combining the plots needed for each graph.

Hi,

When you are trying to plot u2, try the following

plot (t2,u2, '--r')

Similarly for p2 and a2

Best Answer

Related Solutions

MATLAB: How do integrate this function over t=0 to t=165

MATLAB: I am trying to combine plots to one graph for u, p and a. So i need three separate graphs in total but im having trouble combining the plots needed for each graph.

Related Question