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Calculators TI89 titanium logarithms

  1. Feb 29, 2012 #1
    First of all I would like to share this because I randomly found it and I commonly see that people approach base changes of common logs on the ti89 titanium in a very different way.
    Scroll half way down page 2 http://education.ti.com/xchange/AUS-NZ/Mathematics/Number/12250/SomehelpQAontheTI89.pdf [Broken]
    Also, the command "Diamond" and then 7 opens the log() function on ti89 titanium

    Ok on to my question.

    is there a quick way to enter this equation and simplify?

    5lnx+6lny-4lnz =

    The answer is ln(x^5*y^6/z^4)
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Feb 29, 2012 #2
    You lose some accuracy if you use complex numbers, but one easy way is to do ln(e^(5 ln x + 6 ln y - 4 ln z)). Use diamond-x for e^, or CHAR-MATH-5 also gives you the correct e.

    This is just a simple algebra trick: ln(e^x)) = x, but the calculator doesn't try to simplify anymore. If you do e^ln(x), your domain is limited to positive numbers, and the calculator changes the format again.
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