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Math Help - domain and range

  1. #1
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    domain and range

    would the doman and range of

    f(x)= square root of x


    and


    f(x) absolute value of x


    be both ( sideways 8 , sideways 8 ) ???
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  2. #2
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by rj2001 View Post
    would the doman and range of

    f(x)= square root of x
    the domain is the set of x values for which the function is defined.

    what x's work here?

    the range is the set of y values for which the function is defined. what is the range of possible outcomes of the function above?

    f(x) absolute value of x
    follow the same hint above, what do you get?
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  3. #3
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    - sideways8 < x < sideways 8

    im forgetting the x and y in between?

    got it thanks
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by rj2001 View Post
    - sideways8 < x < sideways 8

    im forgetting the x and y in between?

    got it thanks
    umm, no you don't

    is that your answer for the first question? if so, that's wrong

    Hint: you cannot take the square root of a negative number (this defines the domain)
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  5. #5
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    thats infinity in case you dont know and its this ∞ which conveniantly happens to be alt + 236 or alt 8734 on most computers.
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by ffezz View Post
    thats infinity in case you dont know and its this ∞ which conveniantly happens to be alt + 236 or alt 8734 on most computers.
    i know what the user means by "sideways 8", he means infinity

    i'm saying that's the wrong answer
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  7. #7
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    umm, no you don't lol


    domain x > 0 range [ 0, ∞ ) ??


    domain ( - ∞ ,∞) range [0 ,∞) ?
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  8. #8
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    so would f (x) = x^2 +3 be


    domain
    [-3 , 3)

    range
    [0 , ∞)


    ????
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  9. #9
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by rj2001 View Post
    umm, no you don't lol


    domain x > 0 range [ 0, ∞ ) ??


    domain ( - ∞ ,∞) range [0 ,∞) ?
    Close. The domain of \sqrt{x} is x \geq 0, or  [0, \infty). (You can take the square root of 0, right? So it's in the domain.) You have the range correct.

    You have the absolute value function's domain and range correct.

    -Dan
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  10. #10
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by rj2001 View Post
    so would f (x) = x^2 +3 be


    domain
    [-3 , 3)

    range
    [0 , ∞)


    ????
    Is there any restriction on squaring a number? And what is the lowest value of your function? (Hint: it isn't 0.)

    -Dan
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  11. #11
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    Quote Originally Posted by rj2001 View Post
    so would f (x) = x^2 +3 be


    domain
    [-3 , 3)

    range
    [0 , ∞)


    ????
    or okay so this would be domain all real #s ?>?


    range greater or equal to 3?
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  12. #12
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by rj2001 View Post
    or okay so this would be domain all real #s ?>?


    range greater or equal to 3?
    Yup!

    -Dan
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