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C3 Functions question - what is domain of function watch

    • Thread Starter

    hi guys,

    range of g(x) >1

    what is its domain?

    [the answer is x > 2]

    any pointers as to how to get to the answers? i tried substituting g(x) for 1 but that gives 7 = 0


    If x = 2 then we have 0 as the denominator which would not be defined and therefore not every element of the set A would be mapped to exactly one element of set B. because of this x >2

    Since the range is greater than 1, the function must always take a positive value. This rules out -5 \leq x < 2, the values for which the denominator is negative and the numerator is non-negative. Also x=2 is not possible since as Core said the denominator is 0.

    Now think about the other possible values of x (for which the function is positive). There are two cases: x < -5 and x>2. Is g(x) > 1 for these values?
    • Thread Starter

    thanks guys will look into it tomorrow. much appreciated
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Updated: March 17, 2011

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