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