Re: Re: can anyone solve this equation?

*To*: mathgroup at smc.vnet.net*Subject*: [mg58187] Re: [mg58159] Re: can anyone solve this equation?*From*: Chris Chiasson <chris.chiasson at gmail.com>*Date*: Tue, 21 Jun 2005 06:03:24 -0400 (EDT)*References*: <d8rhj9$i7n$1@smc.vnet.net> <200506200952.FAA26966@smc.vnet.net> <acbec1a4050620141519a78e91@mail.gmail.com> <p06230935bedd38f9b92d@130.95.156.21>*Reply-to*: Chris Chiasson <chris.chiasson at gmail.com>*Sender*: owner-wri-mathgroup at wolfram.com

Yes, I was just wondering about how you were able to visualize the equation, breaking it into appropriate constants. I will search the archives and see if anyone has come up with a general method for braking things into constants. (something like: SubstituteConstants[expr,Nonconstants->{a,b,e}], where the result would be the expression and a list of replacement rules that could be used to "restore" the original expression) I (think I) once ran into an equation/problem where the answer was a product log of a constant, but if that constant was given to Mathematica as the addition of two other constants, it would return the expression unsolved. On 6/20/05, Paul Abbott <paul at physics.uwa.edu.au> wrote: > >I agree that subscripted expressions look better. However, I run into > >many instances where Mathematica does not treat subscripted variables > >as symbols. > > Symbolize in Utilities`Notation` is designed to do exactly that (and > in some display formats, such as InputForm, it automatically actually > uses \[UnderBracket] anyway). > > >Notation commands with appropriate pattern matching can > >take care of converting the unbracketed expressions to more easily > >readable ones, but I didn't want to complicate the situation any more > >than it already was. > > Indeed -- to even read and digest your expression I used > pattern-matching several times to reduce the expression to something > more manageable. > > Cheers, > Paul > > >Sincere thanks to both Paul and Pratik for the solutions; I will be > >testing them shortly. > > > >On 6/20/05, Paul Abbott <paul at physics.uwa.edu.au> wrote: > >> In article <d8rhj9$i7n$1 at smc.vnet.net>, > >> Chris Chiasson <chris.chiasson at gmail.com> wrote: > >> > >> > Can anyone solve the following equation (for theta_4)? > >> > >> Essentially, you are solving the equation > >> > >> FullSimplify[Solve[a - Cos[t] - Sqrt[R^2 - Sin[t]^2] == x, t]] > >> > >> where x = 2 n rhs/d is a constant multiple of your right-hand side, rhs, > >> t is theta_4, and a = R + 2/(c - 1) + 1. This is, of course, trivial. I > >> expect that Solve struggles with your expression because of the length > >> and/or complexity of rhs. > >> > >> To me, using \[UnderBracket] makes your input expression unreadable. > >> Only an engineer would work with such expressions! > >> > >> Personally, I like using subscripted expressions in Mathematica. They > >> are not without their difficulties and subtleties -- but are preferable > >> to using \[UnderBracket]. > >> > >> Cheers, > >> Paul > >> > >> -- > >> Paul Abbott Phone: +61 8 6488 2734 > >> School of Physics, M013 Fax: +61 8 6488 1014 > >> The University of Western Australia (CRICOS Provider No 00126G) > >> AUSTRALIA http://physics.uwa.edu.au/~paul > >> http://InternationalMathematicaSymposium.org/IMS2005/ > >> > >> > > > > > >-- > >Chris Chiasson > >http://chrischiasson.com/ > >1 (810) 265-3161 > > > -- Chris Chiasson http://chrischiasson.com/ 1 (810) 265-3161

**References**:**Re: can anyone solve this equation?***From:*Paul Abbott <paul@physics.uwa.edu.au>