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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 7: Cứuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu Tính: A = `2^2012` – (`2^2011` + `2^2010` + … + `2` + `1`)

Home/ Toán Lớp 7: Cứuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu Tính: A = `2^2012` – (`2^2011` + `2^2010` + … + `2` + `1`)

Toán Lớp 7: Cứuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu Tính: A = `2^2012` – (`2^2011` + `2^2010` + … + `2` + `1`)

Tháng Bảy 20, 2022 Toán học 2 Comments 0 views

Toán Lớp 7: Cứuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu
Tính:
A = 2^2012 – (2^2011 + 2^2010 + … + 2 + 1)

Comments ( 2 )

  1. ngoclanquynh
    ngoclanquynh
    20 Tháng Bảy, 2022 at 9:52 sáng
    Reply
    A= 2^2012 – (2^2011 +2^2010 +…+ 2+1)
    Đặt B=1+2+…+ 2^2010 +2^2011
    =>2B=2 + 2^2 +…+ 2^2011 + 2^2012
    =>2B-B= (2 + 2^2 +…+ 2^2011 + 2^2012)-(1+2+…+ 2^2010 + 2^2011)
    =>B=2^2012 -1
    =>A=2^2012 -(2^2012-1)
    =>A=2^2012- 2^2012 +1
    =>A=0+1
    =>A=1
     

  2. thaolanphuobg
    thaolanphuobg
    20 Tháng Bảy, 2022 at 9:52 sáng
    Reply
    Giải đáp:
    $A=1$
    Lời giải và giải thích chi tiết:
    $A=2^{2012}-\bigg(\underbrace{2^{2011}+2^{2010}\ +\,.\!.\!.+\ 2+1}_{\large A’}\bigg)\\\Rightarrow A’=2^{2011}+2^{2010}\ +\,.\!.\!.+\ 2+1\\\Rightarrow2A’=2.(2^{2011}+2^{2010}\ +\,.\!.\!.+\ 2+1)\\\Rightarrow 2A’=2^{2012}+2^{2011}\ +\,.\!.\!.+\ 2^2+2\\\Rightarrow 2A’-A’=(2^{2012}+2^{2011}\ +\,.\!.\!.+\ 2^2+2)-(2^{2011}+2^{2010}\ +\,.\!.\!.+\ 2+1)\\\Rightarrow A’=2^{2012}-1\\\Rightarrow A=2^{2012}-(2^{2012}-1)\\\Rightarrow A=2^{2012}-2^{2012}+1\\\Rightarrow A=1$
    Vậy $A=1$.

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222-9+11+12:2*14+14 = ? ( )

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