Re: Forcing mathematica to output a certain form
- To: mathgroup at smc.vnet.net
- Subject: [mg108107] Re: [mg108064] Forcing mathematica to output a certain form
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Mon, 8 Mar 2010 06:16:01 -0500 (EST)
- Reply-to: hanlonr at cox.net
expr = f[t] + g[t] y'[t] == h[t] y[t]^2;
Reverse[Expand[
Equal @@
Solve[expr /.
f[t] -> -z*g[t], z][[1, 1]]] /.
z -> -f[t]/g[t]]
Derivative[1][y][t] - (h[t]*y[t]^2)/g[t] == -(f[t]/g[t])
Expand[
(First[expr] - Last[expr])/g[t]] == 0
f[t]/g[t] - (h[t]*y[t]^2)/g[t] + Derivative[1][y][t] == 0
Bob Hanlon
---- Geico Caveman <spammers-go-here at spam.invalid> wrote:
=============
As a result of an Eliminate function, and subsequent (wrapper)
simplification under some conditions, I am getting a non-linear
differential equation.
It looks like:
f(t)+g(t) y'(t)=h(t) y^2(t)
Is there a way to force mathematica to output this in the way a
differential equation is best written:
y'(t)+h(t)/g(t) y^(t) = -f(t)/g(t)
or
the transposed form with zero on RHS ?