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 Author Comment/Response Lazaros M. 06/17/12 09:41am OK guys, here's the thing, mathematica does not return a solution for this system of dif.equations DSolve[{p11'[t] == 2*p12[t] - (1/r)*p12[t]^2, p12'[t] == p22[t] - (w^2)*p11[t] - 2*z*w*p12[t] - (1/r)*p12[t]*p22[t], p22'[t] == -2*(w^2)*p12[t] - 4*z*w*p22[t] - (1/r)*p22[t]^2 + (w^4)*q, p11[0] == 0, p12[0] == 0, p22[0] == 0}, {p11[t], p12[t], p22[t]}, t] Can anyone please try it on your system and tell me if u have the same problem? i Also tried with the NDSolve function NDSolve[{p11'[t] == 2*p12[t] - (1/r)*p12[t]^2, p12'[t] == p22[t] - (w^2)*p11[t] - 2*z*w*p12[t] - (1/r)*p12[t]*p22[t], p22'[t] == -2*(w^2)*p12[t] - 4*z*w*p22[t] - (1/r)*p22[t]^2 + (w^4)*q, p11[0] == 0, p12[0] == 0, p22[0] == 0}, {p11[t], p12[t], p22[t]}, {t, 0, 10}] but i get the error message:NDSolve::ndnum: Encountered non-numerical value for a derivative at t == 0.` I greatly appreciate your help Laz. (i use mathematica 8.0) (of course, VariationalMethods is turned on) URL: ,

 Subject (listing for 'Problem with DSolve') Author Date Posted Problem with DSolve Lazaros M. 06/17/12 09:41am Re: Problem with DSolve jf 06/20/12 10:58am
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