Đề:Tính tổng A=2+2^2+2^3+…+2^100

Question

Đề:Tính tổng
A=2+2^2+2^3+…+2^100

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Ladonna 4 years 2020-10-13T15:00:12+00:00 2 Answers 136 views 0

Answers ( )

  1. Latifah
    0
    2020-10-13T15:01:31+00:00
    Reply

    Đáp án:

    0^101

    Giải thích các bước giải:

    Ta có :

    A=2 + 2^2 + 2^3+…..+ 2^100

    2A=2^2 + 263 + 2^4 + … + 2^ 101

    2A-A =(2^2+2^3+2^4+…+2^100)-(2^2+^3+…+2^100)

    A=2^101-2

    A=0^101

  2. Philomena
    0
    2020-10-13T15:01:32+00:00
    Reply

    $A=2+2^{2}+2^{3}+…+2^{100}$

    $2A=2×(2+2^{2}+2^{3}+…+2^{100}$

    $2A=2×2+2×2^{2}+2×2^{3}+…+2×2^{100}$

    $2A=2^{2}+2^{3}+2^{4}+…+2^{101}$

    $A=2A-A=(2^{2}+2^{3}+2^{4}+…+2^{101})$

                   $-(2+2^{2}+2^{3}+…+2^{100})$

    $=>A=2^{101}-2$

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )