Re: ODE in mathematica. what is wrong?

*To*: mathgroup at smc.vnet.net*Subject*: [mg91324] Re: ODE in mathematica. what is wrong?*From*: "Kevin J. McCann" <Kevin.McCann at umbc.edu>*Date*: Fri, 15 Aug 2008 06:55:25 -0400 (EDT)*Organization*: University System of Maryland*References*: <g813bb$4r$1@smc.vnet.net>

Several things are wrong. First, you didn't put spaces between things like rho and y, where I assume you meant to multiply. Second, for a numerical integration everything must be a number (except y and its derivatives); so, you need to specify hbar, rho, epsilon,k, ... Those are just the syntax issues. BTW, if you are going to use subscripted things like y_sub_o you need to use the Notation package and Symbolize them. Now, your differential equation set has multiple equations for y'[x]. Is that what you really meant? I am not sure what problem you are solving here. Perhaps one second order differential equation with different sets of initial conditions? I am not sure. Kevin hoi-su jung wrote: > Hi, > I am a freshman of Mathematica, I need help here... > > I met such problem as: > > NDSolve[{ y'[x] == -\[Rho]y[x], y[0] == Subscript[y, 0], > I\[HBar] y'[x] == \[Epsilon]y[x], y[0] == Subscript[y, 0], > y''[x] + 2 \[Rho]y'[x] + k^2 == 0, y'[0] == Subscript[g, 0]}, y, x] > NDSolve::dvnoarg: The function y appears with no arguments. > > How to Handle??? >