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    What is the answer to 16/9 ^ 1/2? Is it + 4/3 and - 4/3????
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    (Original post by Qwerty11999999)
    What is the answer to 16/9 ^ 1/2? Is it + 4/3 and - 4/3????
    Just +4/3.
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    it's 4/3
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    (Original post by zayn008)
    You're absolutely correct
    So is it the + and - answer. Keep getting confused.
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    (Original post by Qwerty11999999)
    So is it the + and - answer. Keep getting confused.
    Refer to my answer.

    (Original post by RDKGames)
    Just +4/3.
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    (Original post by RDKGames)
    Refer to my answer.
    Oh ok thanks, i was just wondering because (-4/3)^2 = 16/9. So therefore there must be a - answer.
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    (Original post by zayn008)
    Both, because when you square root 4 for example you can have 2 but if you square -2 (-2 * -2) you'll get positive 4 as well so there's 2 possibities and you must list both or you'll lose an easy mark! Technically you'd say 'Or' rather than 'and'. They like doing this in C1 with rearrangement questions, I would write it as +/- 4/3
    Thanks and yes thats exactly how i wrote out my answer. Cheers for advice.
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    (Original post by Qwerty11999999)
    Oh ok thanks, i was just wondering because (-4/3)^2 = 16/9. So therefore there must be a - answer.
    Nope.

    Here is a graph of y=\sqrt{x}. As you can see, there are no negative y values.

    If you had an equation of x^2=\frac{16}{9} then x=\pm \frac{4}{3} (-ve and +ve) are both solutions.

    Name:  SADsad.PNG
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    (Original post by Qwerty11999999)
    So is it the + and - answer. Keep getting confused.
     (\frac{16}{9})^\frac{1}{2} = \sqrt{ \frac{16}{9} } = \frac{4}{3}

    When you have the square root, the answer is only the principal solution which is positive. For example,  \sqrt{x^2} = +x or the mod of x.
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    (Original post by Qwerty11999999)
    Thanks and yes thats exactly how i wrote out my answer. Cheers for advice.
    You may find this thread useful
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    (Original post by zayn008)
    Both, because when you square root 4 for example you can have 2 but if you square -2 (-2 * -2) you'll get positive 4 as well so there's 2 possibities and you must list both or you'll lose an easy mark! Technically you'd say 'Or' rather than 'and'. They like doing this in C1 with rearrangement questions, I would write it as +/- 4/3
    Nope nope nope.

    http://www.thestudentroom.co.uk/show...5#post64637655
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    Ok thanks what about 25^ -3/2. What would that be? Just +1/125
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    (Original post by Qwerty11999999)
    Ok thanks what about 25^ -3/2. What would that be? Just +1/125
    Yes.
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    Wow thanks I've been doing it wrong all this time. Guess I've never been called out because the mark schemes condone it but it's useful to know, didn't realise you only did +/- with algebrea, cheers 👍🏼
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    (Original post by RDKGames)
    Yes.
    Ok thanks, its just that my book says that you should have a + and - answer.
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    (Original post by Qwerty11999999)
    Ok thanks, its just that my book says that you should have a + and - answer.
    Depends what the question is. If it's only the root of 16/9 by itself then it's just +4/3.

    If it's like x^2=16/9 then x=+4/3 and x=-4/3
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    It is true that (-4/3)squared takes you back to 16/9 but by convention the square root always refers to the positive part. (Another way to write mod x is square root of x^2, try it on desmos!)
 
 
 
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