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Math Help - ti 89 help

  1. #1
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    ti 89 help

    I cannot figure out how to input a cube root into this calculator. I can do it with my ti 83 but it converts it into decimals. I need the cube root in front of the square root sign.
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  2. #2
    A riddle wrapped in an enigma
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    Quote Originally Posted by saltflat View Post
    I cannot figure out how to input a cube root into this calculator. I can do it with my ti 83 but it converts it into decimals. I need the cube root in front of the square root sign.
    Hi saltflat,

    If you don't have a cube root function like the TI-83/84 has, then just raise the base to the one-third power.

    Example: Cube root of 27 = 27^{\frac{1}{3}}
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  3. #3
    Super Member bigwave's Avatar
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    Talking

    the input on the home display would
    be
    8^(1/3)

    will return 2
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  4. #4
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    okay an example of what i need is i have the problem with a cube root of 16 which my book is telling me the answer should be 2 the square root check with my cube root then another two under this. what am i doing wrong.
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  5. #5
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    Quote Originally Posted by saltflat View Post
    okay an example of what i need is i have the problem with a cube root of 16 which my book is telling me the answer should be 2 the square root check with my cube root then another two under this. what am i doing wrong.
    Your problem is that you don't understand the basic algebra of surds.

    \sqrt[3]{16} =  \sqrt[3]{8 \times 2} = \sqrt[3]{8} \times \sqrt[3]{2} = 2 \sqrt[3]{2}.
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