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Algebra Summation Notation...?

Write the given series in summation notation:

a) 23 + 19 + 15 + 11 + 7 + 3

b) 1 - 8 + 27 - 64 + 125

2. Write down the nth term of each sequence suggested by the pattern

1/4, 1/16, 1/64, 1/256

1 Answer

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  • Anonymous
    9 years ago
    Favorite Answer

    1). (a) 23+19+15+11+7+3=summation1to6(27-4n)

    (b) 1-8+27-64+125=summation from

    1 to 5 of[{(-1)^(n-1)} (n)^3]

    Note the expression within [ ] carefully!

    (since (-1)^0=1, (-1)^1=-1 etc.)

    2) given sequence can be written :

    (1/4), (1/4)^2 ,(1/4)^3 ,(1/4)^4.........

    OBVIOUSLY nth term is (1/4)^n.

    P.S. You have mentioned words' EACH sequence' in second question. You mentioned ONLY one sequence. Then, is there any sense of ' EACH sequence' ?

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