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I have a calculus question?

Show that the sequence defined by a1 = 2, a(n +1) = (1/[3-an]) satisfies 0 < an <= 2 and is decreasing. Deduce that the sequence is convergent and find it’s limit.

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  • ?
    Lv 6
    1 decade ago
    Favorite Answer

    a1 = 2

    a(n+1) = 1/(3-an) , where 0<an<=2

    You can show the sequence is convergent and is decreasing by find a few numbers.

    a2 = a(1+1) = 1/(3-a1) = 1/(3-2) = 1/1 = 1

    a3 = a(2+1) = 1/(3-a2) = 1/(3-1) = 1/2

    a4 = a(3+1) = 1/(3-a3) = 1/(3-0.5) = 2/5

    a5 = a(4+1) = 1/(3-a4) = 1/(3-0.4) = 5/13

    And yes you can see that it is decreasing and getting closer to 0.

    lim(n->infi) [1/(3-an)] = 1/infi = 0

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