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Math Help - domain of a function

  1. #1
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    domain AND RANGE of a function

    f(x)= the square root of x plus 3


    x + 3 is under the radical.

    thanks
    Last edited by falloutatthedisco; August 17th 2008 at 04:30 PM.
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  2. #2
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    Quote Originally Posted by falloutatthedisco View Post
    f(x)= the square root of x plus 3


    x + 3 is under the radical.

    thanks

    anything under the square root needs to be greater than 0.
    x + 3 > 0
    x > -3 is the domain
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  3. #3
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    ooh yes, I remember that now.

    now.... how do I find the range?

    here's the dilemma... when you find the inverse of that function, the domain of that should be the range of the original function, so y= x^2 - 3

    the range for that would be all real numbers, but when graphed, it looks like an asymptote approaching 0. how would that work?

    thanks.
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  4. #4
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    the range is all the possible outputs of the function. sqrt(x+3) can result in any positive number as long as x > -3. so

    f(x) >= 0
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