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Maths - OL - Complex Numbers help

  • 07-06-2010 3:44pm
    #1
    Finical
    Registered Users, Registered Users 2 Posts: 1,507 ✭✭✭


    Just got one question from 2006 4(b)(ii) Write in its simplest form: i(i^4+i^5+i^6)

    I looked at the answer on examinations.ie, but I haven't a clue how they managed it. Could someone please help and show how they get the figures in layman's terms. :pac:


Comments

  • #2
    SYLT
    Registered Users, Registered Users 2 Posts: 123 ✭✭SYLT


    -1. I think.


  • #3
    MariaBabii
    Closed Accounts Posts: 104 ✭✭MariaBabii


    i(i4 + i5 + i6) = i5 + i6 + i7 = i(i4) + i2(i4) + i3(i4) = i + (-1) + (-i) = -1

    in the sum .. i4 is the equivalent to 1 (i4=1)

    :D


  • #4
    Reillyman
    Closed Accounts Posts: 834 ✭✭✭Reillyman


    [latex] i(i^4+i^5+i^6)[/latex]

    [latex]= i^5+i^6+i^7[/latex]

    [latex]= i-1-i[/latex]

    [latex]= -1[/latex]


  • #5
    Emmpty
    Registered Users, Registered Users 2 Posts: 49 ✭Emmpty


    i^4=1
    i^5=i
    i^6=-1
    so the bracket added up is i
    i x i = i^2
    which equals -1

    You just have to break it down for yourself.


  • #6
    Finical
    Registered Users, Registered Users 2 Posts: 1,507 ✭✭✭Finical


    Thanks a mill everyone, sorted now. :)


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