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Math Help - Y-intercepts of this function

  1. #1
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    Y-intercepts of this function

    f(x)=7(x-4)^{\frac{3}{4}} - 3(x-4)^{\frac{7}{4}}

    Do the y-intercepts exist for this function? According to wolframalpha they do, but I don't see how that's possible.
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  2. #2
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    Quote Originally Posted by youngb11 View Post
    f(x)=7(x-4)^{\frac{3}{4}} - 3(x-4)^{\frac{7}{4}}

    Do the y-intercepts exist for this function? According to wolframalpha they do, but I don't see how that's possible.
    what did you enter into wolfram?
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  3. #3
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    On the y-axis x co-ordinate is zero. So find f(x).
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    Quote Originally Posted by skeeter View Post
    what did you enter into wolfram?
    7 (x - 4)^(3/4) - 3 (x - 4)^(7/4)

    But there are no y-intercepts, right?
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    Quote Originally Posted by sa-ri-ga-ma View Post
    On the y-axis x co-ordinate is zero. So find f(x).
    But how can you evaluate (-4)^{\frac{3}{4}}
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  6. #6
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    Quote Originally Posted by youngb11 View Post
    7 (x - 4)^(3/4) - 3 (x - 4)^(7/4)

    But there are no y-intercepts, right?
    answer my question, please.
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  7. #7
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    Quote Originally Posted by skeeter View Post
    answer my question, please.
    Exactly what I posted:

    7 (x - 4)^(3/4) - 3 (x - 4)^(7/4)
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  8. #8
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    You are correct in that there are no y-intercepts. Skeeter wants you to write exactly what you entered into Wolfram: somewhere, there must have been a mistake with the way you presented your formula to Wolfram or there was a misinterpretation of the formula on WA's part.
    Try writing the exponents in decimal form.
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