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MathGroup Archive 1998

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Re: calculation


  • To: mathgroup@smc.vnet.net
  • Subject: [mg12017] Re: calculation
  • From: "Stephen P Luttrell" <luttrell@signal.dra.hmg.gb>
  • Date: Fri, 17 Apr 1998 03:40:52 -0400
  • Organization: Defence Evaluation and Research Agency
  • References: <6gr69a$8lo@smc.vnet.net>

>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?


Try using FindRoot.

FindRoot[.001422409738*R^(73/80)*(R^(1/2)-1)^(-13/40) == .04,{R,2}]

gives the answer

{R -> 81.2677}

====================================================

Stephen P Luttrell
luttrell@signal.dra.hmg.gb
Adaptive Systems Theory                           01684-894046 (phone)
Room EX21, DERA                                    01684-894384 (fax)
Malvern, Worcs, WR14 3PS, U.K.
http://www.dra.hmg.gb/cis5pip/Welcome.html




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