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  • To: mathgroup at smc.vnet.net
  • Subject: [mg41867] Re:
  • From: Selwyn Hollis <selwynh at earthlink.net>
  • Date: Sat, 7 Jun 2003 11:44:52 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Riccardo,

I'm afraid the best you'll ever get is something like this:

x0 = 3;
Table[{t, x0 = x/.FindRoot[Cot[x] + x == Cos[t], {x,x0}]}, {t,0,6.3,.1}]

soln = Interpolation[%]

Plot[soln[x], {x, 0, 2*Pi}]

-----
Selwyn Hollis
http://www.math.armstrong.edu/faculty/hollis



On Friday, June 6, 2003, at 09:50  AM, Bartolini, R (Riccardo) wrote:

> I have to solve the following transcendental equation
>
>
>
> Cot[x] + x = g(t)
>
>
>
> where g(t) is a function of t (e.g. Cos[t]) and I''d like
>
> to get x as a function of t. Solve and Findroot do not
>
> seem to allow x to be defined as a function of t.
>
> Thanks in advance
>
>
>
>
>
> Riccardo Bartolini
>
> Diamond Light Source Ltd
>
> Tel. +44 (0)1235 778073
>
> Fax +44 (0)1235 446967
>
>
>
>

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From: "Jeremy Foster" <jeremyrfoster at hotmail.com>
To: mathgroup at smc.vnet.net
Subject: [mg41867] Domain Test
  using "From" header
	tests=PRIORITY_NO_NAME,SEMIFORGED_HOTMAIL_RCVD
	version=2.55

Is there any way to test whether or not a given value is in the domain of a
certain function? For instance, is f[-1] defined where f[x_]:=1/Log[x]?
(false)

Thanks,
Jeremy


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