Арифметическая прогрессия

Discussion in 'Болталка' started by Топе, 13 Dec 2011.

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  1. Топе

    Топе Banned

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    Найдите a1 и d арифметической прогрессии, в которой


    a5-a3=-4 ;
    a2*a4=-3
    (система)
     
    #1 Топе, 13 Dec 2011
  2. moodoone

    moodoone Member

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    a1+4d-a1-2d=-4
    2d=-4
    d=-2

    (a1+d)(a1+3d)=-3
    (a1-2)(a1-6)=-3

    a1^2-8a1+15=0
    D=64-60=4
    a11=3
    a12=5

    a1=3
    d=-2

    a1=5
    d=-2
     
    #2 moodoone, 13 Dec 2011
  3. Топе

    Топе Banned

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    Спасибо
     
    #3 Топе, 13 Dec 2011
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