Re: Simple ODE with time-dep BC

*To*: mathgroup at smc.vnet.net*Subject*: [mg77980] Re: Simple ODE with time-dep BC*From*: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>*Date*: Thu, 21 Jun 2007 05:30:28 -0400 (EDT)*Organization*: The Open University, Milton Keynes, UK*References*: <f5as8d$9kj$1@smc.vnet.net>

Apostolos E. A. S. Evangelopoulos wrote: > Hello all, > > I'm having 2 problems with solving the following ordinary differential equation: > > h*h'[t]==-a*h^2+c > > Problem 1: > Mathematica doesn't like the form of the above: > DSolve[{h'[t]\[Equal]-a*h[t]+c/h, h[0]\[Equal]0}, h[t], t] ===============================>!!! Must be written h[t] rather than just h. Mathematica is perfectly correct in complaining and quit clear in describing the issue. The correct expression is DSolve[{h'[t] == (-a)*h[t] + c/h[t], h[0] == 0}, h[t], t] > returns > DSolve::dvnoarg : The function h appears with no arguments. More... [snip] Regards, Jean-Marc