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Math Help - Determining whether an equation defines a function of x?

  1. #1
    Member realintegerz's Avatar
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    Determining whether an equation defines a function of x?

    How do i do that?

    1) x^2 - y = 12

    how do i determine whether it defines a function of x?
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  2. #2
    Math Engineering Student
    Krizalid's Avatar
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    Defining that as a function of x is equivalent to say "in terms of x." Hence, isolate y and you'll get a function in terms of x. What's the name of that curve?
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  3. #3
    Member realintegerz's Avatar
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    so i can substitue f(x) as y... OK!
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  4. #4
    Member realintegerz's Avatar
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    ok i have another question...i have a few of these to do and they all look like their functions of x...i just rearranged the y so that its isolated...so since they all work, does that mean their all functions?
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by realintegerz View Post
    ok i have another question...i have a few of these to do and they all look like their functions of x...i just rearranged the y so that its isolated...so since they all work, does that mean their all functions?
    it depends on how the question was phrased.

    it might mean you should solve for y and then say whether what you have is a function, or just note that anything that does not look like "y = something with x's in it" is not defined as a function of x. then there might be cases where you can't solve for y altogether, in which those are definitely not the functions you want
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