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Student Support Forum: 'Problem using DSolve' topicStudent Support Forum > General > Archives > "Problem using DSolve"

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newbieMath
01/30/09 06:52am

Hello,

I have a problem solving a differential system with mathematica.
In fact it just returns the input without anything more. Any help might be useful.

In[1]:= eqn = {x''[t] - ((1/y[t])*(x'[t])^2) == 0, y''[t] + ((1/y[t])*((x'[t])^2 - (y'[t])^2)) == 0};

In[2]:= res = DSolve[eqn, {x, y}, t]

Out[2]= DSolve[{-(
\!\(\*SuperscriptBox["x", "\[Prime]",
MultilineFunction->None]\)[t]^2/y[t]) +
\!\(\*SuperscriptBox["x", "\[Prime]\[Prime]",
MultilineFunction->None]\)[t] == 0, (
\!\(\*SuperscriptBox["x", "\[Prime]",
MultilineFunction->None]\)[t]^2 -
\!\(\*SuperscriptBox["y", "\[Prime]",
MultilineFunction->None]\)[t]^2)/y[t] +
\!\(\*SuperscriptBox["y", "\[Prime]\[Prime]",
MultilineFunction->None]\)[t] == 0}, {x, y}, t]

Thank you very much in advance

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