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Math Help - square roots

  1. #1
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    square roots

    directions find all of the square roots of each number. if the square root is irrational, round your answer to the nearest hundreth

    1.36
    2.100
    3.117
    4.3/8

    For number 1 I wrote the square root of 36 is 6 and my math teacher marked me wronge. What am i doing wronge and what are the correct answers? Any help would be great
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  2. #2
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    thanks for the help in advance
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  3. #3
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    I presume your math teacher was drunk while marking your work.

    The square root of 36 is 6, dont worry you got it right.

    Bobak
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  4. #4
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    he circiled the word roots and i also got the square root of 100 as 10 marked wronge and the rest of them as well
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  5. #5
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by imbadatmath View Post
    he circiled the word roots and i also got the square root of 100 as 10 marked wronge and the rest of them as well
    the square roots can be + or -, so +/- 10 should be the answer
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  6. #6
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    would the absolute value also work there or does that only apply to variables
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  7. #7
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by imbadatmath View Post
    would the absolute value also work there or does that only apply to variables
    Quote Originally Posted by Jhevon View Post
    the square roots can be + or -, so +/- 10 should be the answer
    to clarify, the square root function always returns positive values. but, if we square root an equation where one side is a square, then we get the +/- square root as the solution. not because the square root function returns negative values, but because the squared term can have negative or positive inputs that returns positive values.

    and so, absolute values do come into play.

    example.

    solve x^2 = 2

    square root both sides

    \Rightarrow \sqrt{x^2} = \sqrt{2}

    note that \sqrt{2} is positive...ALWAYS. but on the left side of the equation, we have \sqrt{x^2}, which happens to be an alternative defintion of |x|, so what we have is

    |x| = \sqrt{2}

    and so, x = \pm \sqrt{2}, since x can be negative or positive, but the absolute value function will return the positive value
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