Re: Do loops in Mathematica

*To*: mathgroup at smc.vnet.net*Subject*: [mg55184] Re: [mg55170] Do loops in Mathematica*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Wed, 16 Mar 2005 05:35:59 -0500 (EST)*Reply-to*: hanlonr at cox.net*Sender*: owner-wri-mathgroup at wolfram.com

Do[p = x /. Solve[x^2+3*x+1 == 0, x]; Return[2p], {i, 1}] {-3 - Sqrt[5], -3 + Sqrt[5]} Bob Hanlon > > From: "dumb_founded" <andreajagger_8 at hotmail.com> To: mathgroup at smc.vnet.net > Date: 2005/03/15 Tue AM 12:22:03 EST > To: mathgroup at smc.vnet.net > Subject: [mg55184] [mg55170] Do loops in Mathematica > > I am having trouble setting up Do loops in Mathematica. Even when I > put in a return statement, I get no output. Below is a concrete > example of code I am putting in: > > Do[{p = Solve[x^2 + 3*x + 1 == 0, x], Return[2*p]}, {i, 1}] > > > I get nothing out of it. > > Here is a sketch of the code I want to construct but am scared to > because of the above problem I keep encountering. > > (1) the first expression in the Do loop calls the FindRoot function on > nonlinear function of x that involves a constant c. The constant c is > in curly brackets at the end of the Do loop specifying a beginning > value for c and an ending value for c. > (2) I take the root found in the previous expression and I use it to > calculate two numerical integrals > (3) I add or subtract the two numerical integrals found in the previous > expressions and I return the value of this expression (and this > expression alone). > > > I am having a headache figuring out this simple chore. Mathematica > simply refuses to behave. > >