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I need help to evaluate sum of arithmetic series

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    Unhappy I need help to evaluate sum of arithmetic series

    sum goes from i = 0 to n-1
    sum = 3 + 4i
    test for n = 501

    this is what I have so far, but I get a syntax error on line: sum = sum + 3+4i


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    Please help. Thank you.
    Last edited by arlu1201; 09-01-2012 at 04:40 AM.

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    Re: I need help to evaluate sum of arithmetic series

    All you need is a formula:

    =2*n^2 + 5*n + 3

    EDIT: That's the sum from 0 to n. For 0 to n-1,

    =2*n^2 + n
    Last edited by shg; 08-31-2012 at 05:28 PM.
    Entia non sunt multiplicanda sine necessitate

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    Re: I need help to evaluate sum of arithmetic series

    I tried that but it did not work. I am not sure if I typed it correctly. Also, it is for n= 881, not 501. I got 2 answers with the formulas you provided. The first one 2646 or something like that, and the second one 0. It says that I can verify the output by : s = n(2.3+ 4(n-1))/2

    Thank you

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    Re: I need help to evaluate sum of arithmetic series

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    B2 and down: =2*A2^2 + 5*A2 + 3

    C2 and down: =2*A2^2 + A2
    Last edited by shg; 08-31-2012 at 07:45 PM.

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    Re: I need help to evaluate sum of arithmetic series

    Thank you, that is the correct answer. However, I do not know how to input that. Do I define A, B & C?
    I am sorry, but this is my second program, and I really do not have idea of what is going on. Thank you for your help.

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    Re: I need help to evaluate sum of arithmetic series

    Quote Originally Posted by qcyo View Post
    sum goes from i = 0 to n-1
    sum = 3 + 4i
    test for n = 501

    this is what I have so far, but I get a syntax error on line: sum = sum + 3+4i


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    Please help. Thank you.
    Hi,

    I want to help you fix your syntax error in your VBA code.

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    You have to use 4*i, not use 4i.
    Last edited by Gervie; 09-01-2012 at 12:39 AM.

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    Re: I need help to evaluate sum of arithmetic series

    qcyo,

    Welcome to the forum.

    I have added code tags to your post. As per forum rule 3, you need to use them whenever you put any code in your post. Please add them in future. If you need more information on how to use them, check my signature.
    If I have helped, Don't forget to add to my reputation (click on the star below the post)
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    Use code tags when posting your VBA code: [code] Your code here [/code]

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    Re: I need help to evaluate sum of arithmetic series

    Gervie.Thank you so much! It works now
    Last edited by qcyo; 09-01-2012 at 11:51 AM. Reason: include name

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