Mathematica 9 is now available
Student Support Forum
-----
Student Support Forum: 'Solving Log Equations' topicStudent Support Forum > General > "Solving Log Equations"

< Previous Comment | Next Comment >Help | Reply To Comment | Reply To Topic
Author Comment/Response
Andrew DuBuisson
10/21/04 5:14pm

Two problems that I see regarding the lack of solution.

First, I dont think that the equation
2*Log[a,x]-Log[a,(x-1)]==Log[a,(x-2)]
has a solution.

Second, your kinda right about the solve function being inable. Solve works best for polynomial and algebraic equations. It can work with logs and exponents if they can be solved in an algebraic fashion.

For instance
Solve[1 Log[a,x]-Log[a,(x-1)]==Log[a,(x-2)]
Returns the answer
x -> 2+(2)^(1/2)

While
Solve[1. Log[a,x]-Log[a,(x-1)]==Log[a,(x-2)]
Returns a message
"The equations appear to involve the variables to be solved for in an essentially non-algebraic way."

Regarding the second part. Mathematica likes to put things into their basic elements. Input Log[a,x] and it will return Log[x]/Log[a]. Where Log is the natural log of course.

Good luck,
Andrew

URL: ,

Subject (listing for 'Solving Log Equations')
Author Date Posted
Solving Log Equations buffer 09/01/04 10:39pm
Re: Solving Log Equations Andrew DuBui... 10/21/04 5:14pm
Re: Solving Log Equations Paul Stysley 10/27/04 1:46pm
Re: Solving Log Equations KENZOU 10/30/04 5:38pm
Re: Solving Log Equations yehuda ben-s... 10/31/04 00:23am
Re: Solving Log Equations Henry Lamb 10/31/04 11:52pm
< Previous Comment | Next Comment >Help | Reply To Comment | Reply To Topic