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    • Thread Starter
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    My family had a debate for the answer for -5^2.

    One came up with -25 and was proved right by her math book and Google.

    However, the other two people came up with 25 and was proved right by the calculator, Yahoo, and the computer calculator.

    Also show your answer, thanks.
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    (Original post by Lolicon)
    My family had a debate for the answer for -5^2.

    One came up with -25 and was proved right by her math book and Google.

    However, the other two people came up with 25 and was proved right by the calculator, Yahoo, and the computer calculator.

    Also show your answer, thanks.
    It depends if you mean (-5)^2 or -(5^2).
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    (-5)^2=25
    -(5^2)=-25
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    -(5^2) is -25, it's simply the negative of 5 squared.
    (-5)^2 is 25, cause multiplying to negative numbers together gives a positive one.

    The squaring function is positive for all real (positive and negative) values of x.
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    It's -25.

    5² = 25.
    -5² = -25.
    (-5)² = 25.

    Powers come before the minus symbol because you're effectively saying -5x5, which is -25.
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    (Original post by Sun Ra and his Arkestra)
    -(5^2) is -25, it's simply the negative of 5 squared.
    (-5)^2 is 25, cause multiplying to negative numbers together gives a positive one.

    The squaring function is positive for all real (positive and negative) values of x.
    Fail.
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    Is it not just a case of convention?

    -5^2 = -1.(5^2) = -25

    (-5)^2 = (-5).(-5) = 25
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    You've written it quite ambiguously, that's why.
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    PS Helper
    BIDMAS- brackets, indices, division, multiplication, addition, subtraction.

    Ergo the indices come before the multiplication and the answer is -25.

    Or I'm talking out my arse and you should just pay attention to everyone else...
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    (Original post by Ice_Queen)

    Or I'm talking out my arse and you should just pay attention to everyone else...
    Oh dear! The unary operator has lower precedence than exponentiation, and operates on the result of 5^2.

    If you don't believe me go here: http://mathforum.org/library/drmath/view/53194.html

    The reason calculators get it wrong so often is that they use the minus key for two purposes and a zero is always on the display at the commencement of the operation.
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    (Original post by TheRandomer)
    You've written it quite ambiguously, that's why.
    No, it was written quite unambiguously, but only for those that understand the precedence rules for unary operators.
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    Well done OP, this will turn into a massive debate even though the answer is obviously the last but one digit of pi. And everyone knows what that is.
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    (Original post by Good bloke)
    No, it was written quite unambiguously, but only for those that understand the precedence rules for unary operators.
    O_o
    But to like NORMAL PEOPLE, that could be taken either way. As everyone else has said.
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    (Original post by TheRandomer)
    O_o
    But to like NORMAL PEOPLE, that could be taken either way. As everyone else has said.
    Aren't normal people expected to understand conventional and basic mathematical notation these days?
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    (Original post by Calumcalum)
    It's -25.

    5² = 25.
    -5² = -25.
    (-5)² = 25.

    Powers come before the minus symbol because you're effectively saying -5x5, which is -25.
    FAIL
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    a - x a - is always a +. however a - in front of the overall multiplication means its negative although the multiplication gives a positive answer
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    (Original post by Good bloke)
    Aren't normal people expected to understand conventional and basic mathematical notation these days?
    I do degree level maths, I know what it means. I'm not saying that.
    Perhaps I didn't quite understand the OP's question. *shrug*
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    (Original post by DeanK2)
    FAIL
    Pass, actually.
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    (Original post by Good bloke)
    Pass, actually.
    Perhaps we agree to disagree.
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    (Original post by DeanK2)
    Perhaps we agree to disagree.
    You can agree what you like; this is not a matter of opinion. Look at the link I provided earlier.
 
 
 
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