Solving odes (restricted 3 body problems)

2020 3 25
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更新时间：2020 3 26
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I have been trying to solve these equations -
d2x dt2 = 2 dy dt + x− M(x + E) r3 E − E(x−M) r3 M
d2y dt2 = −2 dx dt + y− My r3 E − Ey r3 M
z1 = x, z2 = dx dt , z3 = y, and z4 = dy dt
but keep getting these errors:-
Unrecognized function or variable 'rE'.
Error in secodef (line 4) zprime=[z(2);2*z(4)+z(1)-((M*(z(1)+E))/rE^3)-((E*(z(1)-M))/rM^3);z(4);-2*z(2)+z(3)-((M*z(3))/rE^3)-((E*z(3))/rM^3)];
Error in odearguments (line 90) f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.
Error in ode45 (line 115) odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);
Error in trial1 (line 13) [t,z] = ode45(@secodef,tspan,Z);
what do I do?

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darova
darova 2020-3-25

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Variables rE and rM should be in the function

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Aneesa Shahbaz
Aneesa Shahbaz 2020-3-26
After I move rE and rM into the function I get this as a result:
Not enough input arguments.
Error in secodef (line 8)
rE = sqrt((z(1)+E)^2 +z(3)^2);
darova
darova 2020-3-26
Can you attach the function?
Aneesa Shahbaz
Aneesa Shahbaz 2020-3-26
The function is this but coming up with the result:
Not enough input arguments.
Error in secodef (line 8)
rE = sqrt((z(1)+E)^2 +z(3)^2);
What do I do?
darova
darova 2020-3-26
Works for me
>> secodef(1,[1 2 3 4])
ans =
2.0000
8.9685
4.0000
-1.0947
Aneesa Shahbaz
Aneesa Shahbaz 2020-3-26
Thank you, I got it to work.
However i am trying to plot a graph but the plot is empty and only 2 points can be shown the earth and the moon.
What do I do?
darova
darova 2020-3-26
Please see the image i made for you. I think there is some connection
Aneesa Shahbaz
Aneesa Shahbaz 2020-3-26
I understand that z1 = x and z3 = y.
But I don't know what to do to get the graph.
darova
darova 2020-3-26
Do you know how to select columns?

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