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Math Help - infinite sum problem

  1. #1
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    infinite sum problem

    i need help to find the sum of 1 to infinity of 4 (-3)to the power of x
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  2. #2
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    Quote Originally Posted by helpless13 View Post
    i need help to find the sum of 1 to infinity of 4 (-3)to the power of x
    No, this is not clear. It seems to be asking for:

    \sum_{r=1}^{\infty} 4 \times (-3)^r

    which is not convergent.

    RonL
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  3. #3
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    not clear

    it isn't clear but I have a formula that says if k<1 , k being the common ratio than the sum is

    A1
    1-K which is -3 and I don't know if that is right
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  4. #4
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    Quote Originally Posted by helpless13 View Post
    it isn't clear but I have a formula that says if k<1 , k being the common ratio than the sum is

    A1
    1-K which is -3 and I don't know if that is right
    It's |k| (absolute value) that has to be <1.
    Here, |-3|=3 > 1.
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  5. #5
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    Reply

    so does that mean then that a solution does not exist
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  6. #6
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    Quote Originally Posted by helpless13 View Post
    so does that mean then that a solution does not exist
    Is that not what was said?

    RonL
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