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Write down a value of x for which x1/3 is (i) rational, (ii) irrational watch

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    Please can someone show me how to work this out:

    Write down a value of x for which x1/3 (x to thepower of one third) is
    (i) rational
    (ii) irrational.

    Thanks
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    (Original post by nettogrof)
    Please can someone show me how to work this out:

    Write down a value of x for which x1/3 (x to thepower of one third) is
    (i) rational
    (ii) irrational.

    Thanks
    For (i), think about a cube root that gives you a whole number. For (ii), thing about one that leaves you with ugly decimals.
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    (Original post by nettogrof)
    Please can someone show me how to work this out:

    Write down a value of x for which x1/3 (x to thepower of one third) is
    (i) rational
    (ii) irrational.

    Thanks
    For i) just write down any number that is a perfect cube and for part ii))= write down a number which is not a perfect cube.
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    too late again ...
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    (Original post by nettogrof)
    Please can someone show me how to work this out:

    Write down a value of x for which x1/3 (x to thepower of one third) is
    (i) rational
    (ii) irrational.

    Thanks
    Hint: if  \displaystyle x^{\frac{1}{3}} is a surd then it is irrational

    so rephrase the questions to

    i) find a value of x such that x^1/3 isnt a surd

    i) find a value of x such that x^1/3 is a surd
 
 
 
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