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domain and range watch

    • Thread Starter

    im really confused about certain ways to get the domain of a function. how do you tell when it is a one tail or two tail domain? and when do you use the inequalities < and > or <_ and >_?

    also how do you find the range?

    The range of the function is the y-co-ordinates that the function produces.
    I am not sure what you're talking about with a one-tail or two tail domain though.

     f(x) = 3x^2 + 2 has a domain of x e R (x is a real number) and a range of  f(x) \ge 2

    The inverse function,  f^{-1}(x)  = \sqrt {\frac{1}{3} (x-2)}  has a domain of  x \ge 2 since you can only put positive numbers under the square root sigh, and it has a range of  f(x) \ge 0 since you will only get a positive answer. (You can only find the inverse of a function if each value of x produces only one value of f(x), which means the function is called one to one, and so you can't have +/- before the square root sign. )
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Updated: January 10, 2008

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