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Calculators Need help with TI-89 Titanium

  1. May 19, 2007 #1

    I'm working out some problems on my TI-89 Titanium, and I've run into a roadblock.

    How do I put a base for a log?

    Thanks a lot.
    Last edited: May 20, 2007
  2. jcsd
  3. May 20, 2007 #2
    ln(thing you want the log of) / ln(base of the log)

    As far as I know, that's the only way to do it on a TI. but it's not hard.
  4. May 20, 2007 #3
    That's the way I do it; just the standard log change of base formula. So ln(2) is just the log of 2, and ln(2)/ln(10) is log of 2, base 10. You can also see that ln(2)/ln(e), the base e log which is the natural log, will be just ln(2) since ln(e) evaluates to 1.
  5. May 22, 2007 #4
    I borrow this thread a little if its okey..
    I got a problem with mine TI-89.
    Whay I want to calculate a root i press "diamond + 9 + x + , + y + enter" which should give me x^1/y. But all i get is what i just pressed, i.e. the answer i get is root(x,y). :confused:
    Please help me.
  6. May 22, 2007 #5
    To find a root of x, use the zeros() function. Type zeros(expression,variable), or, alternatively, solve(equation,variable), when the equation is the same expression but set to zero, and the variable is x.

    zeros(4x^2+3x+5,x) or solve(4x^2+3x+5=0,x) returns the roots.
  7. May 22, 2007 #6
    Okey, but do you know where the problem for the root function could lie?
    Could it be any setting?

    EDIT: The problem was that I had changed languege... It now works again.
    Last edited: May 23, 2007
  8. May 24, 2007 #7
    another way to do log is to log(number, base)
  9. May 25, 2007 #8
    That doesn't work for me.
  10. Jun 27, 2007 #9


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    I think he has one of those Apps like Omnicalc to upgrade the features kind of. That's also one way you can do it, just with a comma. Change of base requires a little more typing.
  11. Apr 20, 2010 #10
    if you press the yellow Diamond button and then press 7 then log will show up. much less typing for all you lazy people like me
  12. Mar 10, 2011 #11
    i.e. solve(log(x,8)=2/3,x)

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