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Calculators Newb with a TI-npire CX CAS

  1. Sep 19, 2011 #1
    I'm taking an online "Elementary Algebra" class from my local community college. It's been a few years since I graduated high school and I've forgotten pretty much everything; including my T-84 Silver, which I never took full advantage of its potential anyway.

    So I went out and got myself a new calculator, and for some reason I got the nicest one available; the TI-nspire CX CAS and I am utterly lost. Please excuse my ignorance, I'm about to ask some extremely stupid questions:

    First of all, how you divide?!?! When I try, it gives me the answer as a reduced, improper fraction. How can I convert that to a decimal? Or is there a setting I can change to do it automatically.

    Similarly, how do I add/subtract/multiply/divide fractions on it? To make the line between the numerator and the denominator is it just the รท key?

    Also, I see that there is an "=" button that doesn't actually solve math problems, like the Enter button does. This leads me to believe I can enter entire equations and have the calculator solve for x. Is this true? And if so, how do I accomplish that?

    Finally, will it/how do I get it to do fractional proportions? For example, what buttons would I press to solve this:

    x = _ 5
    9 ** 4
    (ignore the asterisks...I can't make them go away....)

    I apologize for the many stupid questions, thanks in advanced for the help!
    Last edited: Sep 19, 2011
  2. jcsd
  3. Sep 25, 2011 #2
    The TI-nSPIRE gives answers as exact (that's why you get the fractions) for an approximate (decimal) answer, press control-enter instead of enter. (You can also change the default in settings/settings/general/Calculation_Mode for exact or approximate answers.)

    An important feature is that different 'documents' can have different settings, so if for example, you create one document for physics class, all of the general settings can be what you need for physics and the calculator will remember them. Then, you can create another document for algebra class and save all of the settings that are correct there... No more wrong answers because you forgot to change to/from radian-degree angles, etc...

    Entering fractions uses a "template", all of the templates are available as a menu when you press the template button (just to the right of the 9). The shortcut for the fraction template is to press ctrl-(divide).

    The equal sign key can be used to enter equations or to compare the equality of two quantities and return a true/false result. (There is also a := key that assigns a value to a variable.)

    I've had my nSPIRE for a year, and once I learned the different keypresses and shortcuts, I found it much faster & easier to use than my previous TI-8X calculators. (I upgraded to the nSPIRE CX over the Summer for the improved screen).

    You can also type the name of any function using the a-z keys instead of clicking through a bunch of menus... this was a big time saver when solving systems of equations using the rref() function.

    Hope that helps!
  4. Sep 26, 2011 #3
    Thanks! You answered all my questions.

    This is going to make this class an absolute breeze. I need to make sure I actually learn the math and not just let the calc do all the work though, lol.
  5. Jan 27, 2012 #4
    I am also a newb on the Nxpire cx cas. Can someone explain to me how to use pi on this calculator? Everytime I try to use it, for example, multiply to add or subtract with pi it gives me an error. Anyone? thanks
  6. May 17, 2012 #5
    Hey-I just got my TI inspire CX, how do I change the settings so that it will give me answers in simplified radical form? For instance, if I input square root of 12 I want to get 2 times the square root of 3, but I get 3.41... instead. Also, I want it to give me answers in terms of pi, not in decimals. My old TI inspire did this, help? Anyone?
  7. May 23, 2012 #6
    It sounds like it is in "Approximate Mode" and you want to get it into "Exact Mode."

    If you have the manual you can probably look up Mode in the index.

    This description
    http://mathbits.com/mathbits/TINSection/General/Mode.html [Broken]
    might be close enough that you can use it to select Exact Mode and you may also want to do as it describes at the bottom to make that Exact system-wide so it applies to everything you work on.

    If you ever need to get back to decimals you follow the same directions and choose Approximate.
    Last edited by a moderator: May 6, 2017
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