*To*: mathgroup@smc.vnet.net*Subject*: [mg12026] Re: [mg11966] calculation*From*: Bob Hanlon <BobHanlon@aol.com>*Date*: Fri, 24 Apr 1998 01:52:01 -0400

In a message dated 4/17/98 3:21:17 AM, saeedr@stud.ntnu.no wrote: >My name is Saeed and i'm studying physics. I have a problem which ihope >someone can help me with it. I have an equation > >.001422409738*R^(73/80)*(R^(1/2)-1)^(-13/40) == .04 > >i'm using the Solve function in Mathematica 3.0 to solve it for R, but >it calculats endlessly and takes very long time. the question is that >is there any way to optimize this equation or using another function in >Mathematica 3.0 to make it faster to calculate? eqn = .001422409738*R^(73/80)*(R^(1/2)-1)^(-13/40) == .04; Plot[.001422409738*R^(73/80)*(R^(1/2)-1)^(-13/40) - .04, {R, 5, 100}]; FindRoot[eqn, {R, 80.}] {R -> 81.26549297247551} Bob Hanlon