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    • Thread Starter
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    Hello there,

    If I have the answer to a question that is a square root, do I have to use the plus minus sign?

    Question example:

    Rearrange the formula to make r the subject of it.

    A= (pi*r^2)/2

    Do I have to make the answer +/- sqrt((2A)/pi), or is just sqrt((2A)/pi) enough?

    Thanks in advance,

    A.T.
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    Just sqrt, I'd say. I'm pretty sure you just +/- if you're writing it as an unsquare rooted (don't know the actual term) number. So like either sqrt9 or +/-3. If that makes sense,
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    In the marking scheme they put brackets (+/-) on the answer. What does that mean?
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    (Original post by Atham)
    In the marking scheme they put brackets (+/-) on the answer. What does that mean?
    It means they will not deduct a mark if you include the +/- sign.

    Don't though. Think about the physical situation. You really don't want a negative radius.
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    (Original post by AshenSun)
    Just sqrt, I'd say. I'm pretty sure you just +/- if you're writing it as an unsquare rooted (don't know the actual term) number. So like either sqrt9 or +/-3. If that makes sense,
    That isn't correct.

    \sqrt 9 = 3
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    (Original post by Mr M)
    It means they will not deduct a mark if you include the +/- sign.

    Don't though. Think about the physical situation. You really don't want a negative radius.
    Yeah, that is why I left it positive.
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    (Original post by Atham)
    Yeah, that is why I left it positive.
    You did the right thing then.
 
 
 
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