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Calculators TI-89 Differentiation

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  1. Aug 17, 2006 #1
    1. After I launch the "Home" program and enter

    d(x^2,x)

    The calculator spits out -52.4916, a numerical solution. What I want is the algebraic derivative 2x - how do I get to the algebraic derivative?

    2. When I enter sin(60), it gives me -0.304811 as an output. Why does the Ti-89 give a negative result, while the Ti-83 provides me with a positive one?

    Sorry if I'm in the wrong forum. The forum search didn't spit out anything.
     
  2. jcsd
  3. Aug 17, 2006 #2

    chroot

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    1. Make sure you don't have x defined as some constant. If you just enter 'x,' what does it return?

    2. Make sure the calculator is set for degrees, not radians.

    - Warren
     
  4. Aug 17, 2006 #3
    Thank you for your feedback, Warren. You are right, I associated a number with x. How can I make it a variable again?
     
  5. Aug 17, 2006 #4
    I think there's a menu option, I think second then f1, or maybe f5 will give you the option to clear a-z or maybe it's under the var-link think which would be second then "-". The batteries in my 89 are dead so I can't check which one it is, but I'm pretty sure it's one of those.
     
  6. Aug 21, 2006 #5
    I have my TI-89 right here, so I'll look. Yep, go to VAR-LINK and scroll down until you see stored items and you should see "x" there. Delete it and you're good!
     
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