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Re: coding problem

Ming Hong wrote:
> I am trying to solve the following equations:
> xy''+(1+x)y'=0
> xy'(0)=-1/2
> y(Infinity)=0
> Here is what I put into Mathematica:
> Dsolve[{x*y''[x]+(1+x)*y'[x]==0,x*y'[0]==-1/2,y[Infinity]==0},y,x]
> It didn't work and I can not figure out why.
> Thanks for your help!
> Ming
Hi Ming,

*DSolve* must be written with a capital "D" _and_ a capital "S".

Nevertheless, it seems that your equation do not have a solution for the 
given conditions.

DSolve[{x*Derivative[2][y][x] + (1 + x)*Derivative[1][y][x] == 0, 
x*Derivative[1][y][0] == -2^(-1),
    y[Infinity] == 0}, y, x]

Divide::infy: Infinite expression 1/0 encountered.

DSolve::bvnul: For some branches of the general solution, the given 
boundary conditions lead to an empty solution. More...



"5.2 for Microsoft Windows (June 20, 2005)"

Best regards,

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