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MathGroup Archive 1996

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Re: Need help with solving problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg5361] Re: [mg5339] Need help with solving problem
  • From: "Dr. Sergio Miguel Terrazas Porras" <sterraza at campus.cdj.itesm.mx>
  • Date: Thu, 5 Dec 1996 14:50:10 -0500
  • Sender: owner-wri-mathgroup at wolfram.com

Ingimar,
The second line is wrong
2*(2^x)=2^(x+1) and not 4^x

Saludos
Sergio Terrazas

On Wed, 27 Nov 1996, Ingimar Vvlundarson wrote:

> Can anyone help me with this problem?
> 
> (4^x)+(2^x)-2=0
> 
> Everyone can see that x=0 but:
> 
> (4^x)+(2^x)-2=0 =>
> 2*(2^x)+(2^x)-2=0 =>
> 2y+y-2=0 =>      ;(let y=2^x)
> 3y=2 =>
> y=2/3 =>
> 2^x=2/3 =>       ;(let 2^x=y)
> lg(2^x)=lg(2/3) => 
> x*lg(2)=lg(2/3) =>
> x=lg(2/3)/lg(2) Which is not true!!!
> 
> Am I doing something wrong?
> 
> Please E-mail an answer to:
> ingimar.volundarson at mailbox.swipnet.se
> 
> Thanx in advance!
> 
> 
> 


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