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Student Support Forum > General > > "NDSolve"

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Original Message (ID '154190') By Bill Simpson:
In Response To 'Re: Re: Re: Re: NDSolve' --------- I apologize for my mistakes. Here is what I have at the moment In[1]:= n=2; m= .3; κ=2; l= -1.1; ti=0; ts=1000; ph= .8; phd=2.1; xi=3; NDSolve[{2x''[t]/x[t]+(x'[t]/x[t])^2 + κ (y'[t]^2/2 - n Exp[m y[t]]) + κ(l y[t]^3 y'[t])/(3 x[t]^2)==0, y''[t] + 3(x'[t]/x[t])y'[t] + n m Exp[m y[t]] + (l x'[t] y[t]^3)/x[t]^3==0, y[ti]==ph, x[ti]==xi, y'[ti]==phd, x'[ti]== -xi Sqrt[κ/3]Sqrt[((y'[ti]/2)^2 + n Exp[m y[ti]])}, {x, y}, {t, ti, ts}]\) From In[1]:= Solve::incnst: Inconsistent or redundant transcendental equation. After reduction, the bad equation is 12-50 Log[E^(3<<1>>/10]== 0. ... And it is that warning message that worries me. I am guessing that is not a message to ignore. Unfortunately, as it says, this is after NDSolve and Solve have already made changes to your original equations and this was why I could not pinpoint exactly where the problem was. Be careful with this because it is easy to introduce errors when trying to scrape-n-paste Mathematica output into a readable form here.