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Calculators TI-89 Titanium equation Help

  1. Jan 23, 2007 #1
    Okay, when I type in this equation 2(-1.999^2)+5(-1.999) the answer it gives me is -2.003, which would be great, BUT I need it to be more exact, I need it to say -2.002998 (as older calculators do) I've tried all three modes (exact, approx, and auto) and none of them are allowing me more decimal places. Is there a way that I can change how many decimal places my calculator shows??:confused:
    Please help, anyone?!?!
    Last edited by a moderator: Oct 18, 2011
  2. jcsd
  3. Jan 23, 2007 #2


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    Gold Member

    Well first of all its 5(-1.999)-2(-1.999^2) to get -2.002998. I get that answer by using approx. with "float" display digits.

    EDIT: the display digits setting is on the 1st page when you hit "mode"
  4. Jan 23, 2007 #3
    Press up and highlight the answer and then press enter, in the bar at the bottom it should give you the answer to like 15 decimal places, how much more exact to do you need? :D

    Also yes, as ranger said, if you want a more permanent solution, use float 6 or 7. (Or as I just learned, "float" works too) =-)
    Last edited: Jan 23, 2007
  5. Jan 23, 2007 #4
    Also when you press Enter, hit the green diamond button first. That gives you the 'approximate answer' and if you're already doing that, then go to the Mode, display digits, Float 12. It will show all decimal digits up to 12 places (if there are 12) and then it starts rounding.
  6. Jan 24, 2007 #5
    As far as I understand significant digits..here goes:

    I noticed that your inputs are of 4 significant digits accuracity excluding 2, meaning your output should not be in any way more precise(more significant digits) than the input (4 SD). Maybe instead of -1.999 write -1.99900 that should give the result to 6 SD.

    -2.002998 is technically not correct any number in the range of -2.002950 to -2.003049 could be the answer therefore technically you are only allowed to write -2.003.
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