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