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Math Help - Domain & Range Question

  1. #1
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    Question Domain & Range Question

    What is the domain & range of this function ?
    f (x) = 2 + √x-4

    I know that the number under the square root can't be zero or negative.

    Thus far I think that:

    the domain is R=> 4
    the range ? not sure how to calculate
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  2. #2
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    Quote Originally Posted by kbgemini16 View Post
    What is the domain & range of this function ?
    f (x) = 2 + √x-4

    I know that the number under the square root can't be zero or negative.

    Thus far I think that:

    the domain is R=> 4
    the range ? not sure how to calculate
    You have the domain correct.

    The range is not as difficult as you may think. What is the minimum value of your function? The radical cannot be less than zero, so the function is at least two. The sky is the limit as far as a maximum is concerned.
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  3. #3
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    Quote Originally Posted by colby2152 View Post
    You have the domain correct.

    The range is not as difficult as you may think. What is the minimum value of your function? The radical cannot be less than zero, so the function is at least two. The sky is the limit as far as a maximum is concerned.
    ok, so could the range be (5,)
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  4. #4
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    Quote Originally Posted by kbgemini16 View Post
    ok, so could the range be (5,)
    No, the range's minimum would be the minimum of the function which is two.
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  5. #5
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    Quote Originally Posted by colby2152 View Post
    No, the range's minimum would be the minimum of the function which is two.
    I'm getting confused...

    Are you saying the min is 2 because it's 2 + the radical ?
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  6. #6
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    Quote Originally Posted by kbgemini16 View Post
    I'm getting confused...

    Are you saying the min is 2 because it's 2 + the radical ?
    Yes because the minimum value of the radical is zero. It cannot be negative, but it can be zero (at x = 4), so the minimum of the function is two, and that is the bottom of the range.
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  7. #7
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    Quote Originally Posted by colby2152 View Post
    Yes because the minimum value of the radical is zero. It cannot be negative, but it can be zero (at x = 4), so the minimum of the function is two, and that is the bottom of the range.
    I got it now !!!

    Thanks so much ...
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