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Re: How can I solve this equation with Solve or Reduce or whatever for
*To*: mathgroup at smc.vnet.net
*Subject*: [mg128562] Re: How can I solve this equation with Solve or Reduce or whatever for
*From*: Dana DeLouis <dana01 at me.com>
*Date*: Sun, 4 Nov 2012 00:44:01 -0400 (EDT)
*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com
*Delivered-to*: l-mathgroup@wolfram.com
*Delivered-to*: mathgroup-newout@smc.vnet.net
*Delivered-to*: mathgroup-newsend@smc.vnet.net
> ArcTan[Tan[Degree*(180 - 1.5267134447254718*(18.43494882292201 +
> 360*NoOf360Rotations))]] == 0.23101849674392247
> Only want Integer return of NoOf360Rotations AND to equal 108
Hi. Another way might be to move everything to the left-hand side of the equation.
ArcTan[Tan[Degree*(180-1.5267134447254718*(18.43494882292201+360*x))]] - 0.23101849674392247
f=FullSimplify[%]
-0.231018+ArcTan[Tan[2.65037 -9.59262 x]]
Now:
Minimize[{Abs[f],0<x<200},x,Integers]
{2.77556*10^-17,{x->108}}
The value of 2.77*10^-17 is pretty close to zero, and will trigger True if compared at machine precision.
Here's another idea if another problem in the future was not as close to zero.
Table[ f->x, {x,105,110}]
{0.503537->105,
0.335691->106,
0.167846->107,
2.77556*10^-17->108,
-0.167846->109,
-0.335691->110}
Nearest[%,0]
{108}
= = = = = = = = = =
HTH :>)
Dana DeLouis
Mac & Mathematica 8
= = = = = = = = = =
On Friday, November 2, 2012 1:13:06 AM UTC-4, Lea Rebanks wrote:
> Hi All,
>
> Given that the following equation is true.
>
>
> Clear[NoOf360Rotations]
>
> NoOf360Rotations = 108
>
>
> ArcTan[Tan[Degree*(180 - 1.5267134447254718*(18.43494882292201 +
>
> 360*NoOf360Rotations))]] == 0.23101849674392247
>
> TRUE
>
>
> How can I solve this equation with Solve or Reduce or whatever for the
>
> required value NoOf360Rotations = 108
>
> Only want Integer return of NoOf360Rotations AND to equal 108
>
> Any help or advice gratefully received.
>
> Best regards,
> Lea=85
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