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MathGroup Archive 2001

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RE: help: how do you solve a less-or-equal equation

  • To: mathgroup at smc.vnet.net
  • Subject: [mg31011] RE: [mg31001] help: how do you solve a less-or-equal equation
  • From: "David Park" <djmp at earthlink.net>
  • Date: Tue, 2 Oct 2001 01:20:46 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Okke,

Needs["Algebra`InequalitySolve`"]

InequalitySolve[3*x^2 + 2*x + 1 <= 2*x + 5, x]
-(2/Sqrt[3]) <= x <= 2/Sqrt[3]

You will get False is there are no solutions. Sometimes you will get Root
objects. Look them up in Help.

InequalitySolve[-5*x^3 - 3*x^2 + 2*x + 1 <= 2*x + 5, x]
N[%]
x >= Root[4 + 3*#1^2 + 5*#1^3 & , 1]
x >= -1.1772423815220807

David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/

> From: Okke [mailto:kroosu at tref.nl]
To: mathgroup at smc.vnet.net
>
> hello,
> i'm trying the mathematica demo by doing some basic mathematics.
>
> at the moment i'm having problems with a less-or-equal equation.
> Solve[a <= b,x] (with a and b as functions of x) gives an error,
> saying it's not a well-formed equation.
> appearently Solve cant handle the less-than sign.
> how do you solve an equation like this in mathematica?
>
> and can i assign the value to the variable automaticly?
>
> tia,
> --
> Okke <kroosu at tref.nl>
>



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