Re: reduced functionality of Solve
- To: mathgroup at smc.vnet.net
- Subject: [mg44285] Re: reduced functionality of Solve
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Tue, 4 Nov 2003 03:23:58 -0500 (EST)
- Organization: The University of Western Australia
- References: <bnnusd$5vc$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
In article <bnnusd$5vc$1 at smc.vnet.net>,
Andrew Collier <colliera at nu.ac.za> wrote:
> this may be a naive idea but i expected the functionality of software to
> improve with later releases. this, in my opinion, does not seem to be the
> case from mathematica 4.1 to 5.0... or maybe i am just missing something.
5.0 is being more careful that 4.1.
> in a script i have the following bit of code:
>
> -------------------------------------------------------------------------
> F[W_, y_] := Exp[-W(Cos[y]^2/Tp + Sin[y]^2/Tn)]
>
> Tn = 3000;
> Tp = 2000;
>
> Solve[{D[F[W, y], y] Tan[y] == 2 F[W, y], W == 1000 Sec[y] ^ 2}, {W, y}];
> N[%] // TableForm
> -------------------------------------------------------------------------
Replace Solve with Reduce. Reduce gives the complete family of
solutions, including arbitrary constants corresponding to the
non-uniqueness of the solution.
[However, I note tha FullSimplify in Mathematica 5.0 does not simplify
2 ArcTan[Sqrt[(1/3) (4 - Sqrt[7])]]
to
ArcTan[Sqrt[6]]]
but it does verify that
FullSimplify[Tan[2 ArcTan[Sqrt[(1/3) (4 - Sqrt[7])]]] - Sqrt[6]]
returns 0.]
Cheers,
Paul
--
Paul Abbott Phone: +61 8 9380 2734
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