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Thread: Which expression is defined for all real numbers?

  1. #1
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    Which expression is defined for all real numbers?

    Which expression is defined for all real numbers?
    Please explain why the choice that you chose is correct.

    Choice 1)
    x+3/x^2

    Choice 2)
    4/(x-2)^2

    Choice 3)
    5/(x+2)^2

    Choice 4)
    7/x^2+3
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  2. #2
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    Re: Which expression is defined for all real numbers?

    Quote Originally Posted by sontung View Post
    Which expression is defined for all real numbers?
    Please explain why the choice that you chose is correct.

    Choice 1)
    x+3/x^2

    Choice 2)
    4/(x-2)^2

    Choice 3)
    5/(x+2)^2

    Choice 4)
    7/x^2+3
    Please use grouping symbols
    Is choice 4) $\dfrac{7}{x^2}+3$ that is what you posted.
    Or is it $\dfrac{7}{x^2+3}$

    Choice in which the denominator cannot be zero is the correct answer.
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  3. #3
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    Re: Which expression is defined for all real numbers?

    Quote Originally Posted by Plato View Post
    Please use grouping symbols
    Is choice 4) $\dfrac{7}{x^2}+3$ that is what you posted.
    Or is it $\dfrac{7}{x^2+3}$
    It must be the latter for choice 4) to look like that for this problem to have an answer, and I suspect that choice 1)
    had been intended as (x + 3)/x^2, given that choice 4) is missing the required parentheses, even though it would
    not change the answer choice.
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