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Re: newbie: diff equation

• To: mathgroup at smc.vnet.net
• Subject: [mg96986] Re: newbie: diff equation
• From: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>
• Date: Sun, 1 Mar 2009 04:55:26 -0500 (EST)
• References: <200902261301.IAA26650@smc.vnet.net> <go8hpb$ks4$1@smc.vnet.net>

Not only for differential equations, but for all equations.

== is the equals Function, = is the Set function.

Cheers -- Sjoerd

On Feb 27, 1:11 pm, "Ned Lieb" <okty.gy.... at gmail.com> wrote:
> You have to use two equals signs instead of one when inputting a
> differential equation.
>
> -----Original Message-----
> From: Mike [mailto:atkins1... at yahoo.com]
> Sent: Thursday, February 26, 2009 8:01 AM
> Subject:  newbie: diff equation
>
> My problem is very simple, I'm sure someone can help me out quickly. I am
> trying to solve some systems of differential equations a bit like a parti=
cle
> in a box (QM) so I started with this basic problem which I know how to so=
lve
> just to make sure I am entering everything ok, but I can't even get it to
> work.
>
> I want to solve f''[x]= - m^2 f[x]
>
> with f[0] = 0 and f[Pi] = 0
>
> this is obviously only solvable with the condition on m being integer but=
 if
> I do DSolve on the above with the boundary conditions I just get f=0. H=
ow
> can I get mathematica to solve this and give me the conditions on m? I ne=
ed
> to solve much more general problems of this type. I hope someone can help=