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Where am I going wrong

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  • 30-10-2018 9:37am
    #1
    iCrazzy
    Registered Users Posts: 204 ✭✭


    I can't seem to find the correct value of x, I've been at this for 30 minutes, I am not sure if my way of doing it is wrong, if someone can please have a look.

    Thanks in advance.


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    #2
    Michael Collins
    Moderators, Science, Health & Environment Moderators Posts: 1,846 Mod ✭✭✭✭Michael Collins


    Hi iCrazzy,

    Why do you subtract the term gif.download?%285x%5E%7B5n%7D%29%5E0 on line 4?


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    #3
    iCrazzy
    Registered Users Posts: 204 ✭✭iCrazzy


    Michael Collins wrote: »
    Hi iCrazzy,

    Why do you subtract the term gif.download?%285x%5E%7B5n%7D%29%5E0 on line 4?

    Oh crap must be by mistake
    So after leaving that out I get 0.94. But that doesn't seem to be right?
    Thanks for replying


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    #4
    Michael Collins
    Moderators, Science, Health & Environment Moderators Posts: 1,846 Mod ✭✭✭✭Michael Collins


    Your answer of 0.94 is correct (to two decimal places).

    The formula for the sum-to-infinity of a geometric series that you used, a/(1-r), assumes a sum from n = 1 to infinity, with 'a' as the first term (x^5 in this case), and 'r' as the common ratio (also x^5 in this case) - I've kept the constant of 5 outside the summation for simplicity.


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    #5
    TheBody
    Registered Users Posts: 5,619 ✭✭✭TheBody


    Hi op.

    Please see attached.


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    #6
    iCrazzy
    Registered Users Posts: 204 ✭✭iCrazzy


    Michael Collins wrote: »
    Your answer of 0.94 is correct (to two decimal places).

    The formula for the sum-to-infinity of a geometric series that you used, a/(1-r), assumes a sum from n = 1 to infinity, with 'a' as the first term (x^5 in this case), and 'r' as the common ratio (also x^5 in this case) - I've kept the constant of 5 outside the summation for simplicity.

    Thank you so much for your help


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    #7
    iCrazzy
    Registered Users Posts: 204 ✭✭iCrazzy


    TheBody wrote: »
    Hi op.

    Please see attached.

    Thank you for taking the time to do this


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