Hey guys,
I'm in my last year of my physics degree, and part of my dissertation project involves mathematica, modelling the orbital behaviour of a spacecraft using Ion propulsion.
I have 2 coupled differential equations being solved, r''(t) and o''(t), in an NdSolve function (o is pheta in my case, modelling the change in angular momentum). It solves this with no problem, and plots the results fine. My next step is to attain a parametric plot, in which my 2 functions are cos(o)r and sin(o)r, to get the trajectory of my spacecraft along its journey. I have attemped to copy the syntax in the "get help" section and the when evaluated, it just returns a blank graph. What am i doing wrong!?
ParametricPlot[{Evaluate[r[t] /. TotalThrust]* Evaluate[Cos[o[t]] /. TotalThrust], Evaluate[r[t] /. TotalThrust]* Evaluate[Sin[o[t]] /. TotalThrust]}, {t, 0, 10}, PlotRange -> All]
(TotalThrust is the label given to my NDSolve function)
Thanks in advance!
Mike