I'm trying to make an animation showing the path of the moon orbiting around the earth, but I'm having some trouble plotting it. For some reason, Mathematica doesn't give me any error messages but after running the animation it doesn't show anything.
I'm trying to get a similar animation to this:
Here is what I got so far:
m1 = 100/q;
m2 = 1/q;
eqn = {x2''[t] ==
q*m2*(x1[t] - x2[t])/((x2[t] - x1[t])^2 + (y2[t] - y1[t])^2)^(3/2),
y2''[t] ==
q*m2*(y1[t] - y2[t])/((x2[t] - x1[t])^2 + (y2[t] - y1[t])^2)^(3/2),
x1''[t] ==
q*m2*(x2[t] - x1[t])/((x2[t] - x1[t])^2 + (y2[t] - y1[t])^2)^(3/2),
y1''[t] ==
q*m2*(y2[t] - y1[t])/((x2[t] - x1[t])^2 + (y2[t] - y1[t])^2)^(3/2)}
Testek = NDSolve[{eqn, x1'[0] == 0, x1[0] == 0, y1'[0] == 0,
y1[0] == 0, x2'[0] == 0, x2[0] == 100, y2'[0] == 1,
y2[0] == 0}, {x1, y1, x2, y2}, {t, 0, 200}]
Animate[ParametricPlot[
Evaluate[{x1[t], y1[t], x2[t], y2[t]} /. Testek], {t, 0, 200},
PlotRange -> All], {t, 0, 200}];
;in the last line because semicolon is used to hide the ouput. Secondly, you cannot havetbe used twice in the last line; change the first{t, 0, 200}to{t, 0, tfin}and the second one to{tfin, 0, 200}. Thirdly, you should put another list around the coordinates in the last line:{{x1[t], y1[t]}, {x2[t], y2[t]}}. Fourthly, your differential equations are probably wrong because the solution is not periodic. $\endgroup$m2tom1in the first two DEs. Your result should then look like this. $\endgroup$