Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Try solving this log equation using algebra

  1. Jan 13, 2005 #1
    6-2x = 3 * log (x)

    Is it possible to solve such an equation without graphing?
  2. jcsd
  3. Jan 13, 2005 #2


    User Avatar
    Science Advisor
    Homework Helper

    No.Even graphic methods only give an approximate value...

  4. Jan 13, 2005 #3

    Dr Transport

    User Avatar
    Science Advisor
    Gold Member

    try Newton's method (numerical iteration)

    [tex] x_{i+1} = x_{i} - \frac{f(x_{i})}{f'(x_{i})} [/tex]. Write the function as

    [tex] f(x) = 3\log(x) - 6 + 2x [/tex] and

    [tex] f'(x) = \frac{3}{\ln(10)x} + 2 [/tex] (the derivative of the function.

    Choose a number not zero to start and just iterate away.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?