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Math Help - Question on series,pls help to check

  1. #1
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    Question on series,pls help to check

    hi everyone

    need help to verify my working.
    question:
    compute S5 for
    an(limit=infinity,n=1) if 1/(n(n+1))


    my working=
    n=1,= 1/(1(1+1)) =1/2
    n=2,= 1/(2(2+1)) =1/6
    n=3,= 1/(3(3+1)) =1/12
    n=4,= 1/(4(4+1)) =1/20
    n=5,= 1/(5(5+1)) =1/30

    sum = 1/2+1/6+1/12+1/20+1/30 = 5/6

    thank you in advance for all your help
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  2. #2
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    Is this about a sum of fractions? Well, uh... Yes, 1/2+1/6+1/12+1/20+1/30 = 5/6.
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  3. #3
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    He was only asking for a check. The question, as I finally realized, was to find the fifth partial sum.
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  4. #4
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    hi everyone.

    question
    \sum_{n=1}^{infinity} a_n if a_n=1/(n(n+1)).

    is my workings above correct? please help advise..
    Last edited by anderson; January 29th 2010 at 02:28 AM.
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  5. #5
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    Quote Originally Posted by anderson View Post
    thank you for all your response.. did i do it right?]

    how do i insert sigma notation, can someone help me

    please help advise.
    Are you familiar with latex?

    {math}\sum_{p}^{q}a_p{/math}

    Will result in:

    \sum_{p}^{q}a_p
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  6. #6
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    You also posted this under "Calculus" as "Series sum question, is this correct?" Please do NOT double post!
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  7. #7
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    no,that is a different question, please look again. but it all involves S_5.
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