Register Now

Login

Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

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

Toán Lớp 6: Tìm số tự nhiên n để 2n – 1 – 2 – 2 ²- 2 ³-…- 2 mũ 100 =1

Toán Lớp 6: Tìm số tự nhiên n để 2n – 1 – 2 – 2 ²- 2 ³-…- 2 mũ 100 =1

Comments ( 2 )

  1. $\text{Ta có:2n-1-3-2^2-2^3-………-2^100=1}$
    $\text{2n-(1+2^2+2^3+………+2^100)=1}$
    $\text{ta đặt :}$
    $\text{A=1+2^2+…+2^100}$
    $\text{2A=2+2^2+…+2^101}$
    $\text{2A-A=(2+2^2+…+3^101)-(1+2^2+…+2^100)}$
    $\text{A=2^101-1}$

    $\text{⇒2^n-(2^101-1)=1}$
    $\text{⇒2^n-2^101+1=1}$
    $\text{⇒2^n=1-1+2^101}$
    $\text{⇒2^n=2^101}$
    $\text{⇒n=101}$
    $\text{Vậy n =101}$
    $@Lun$            

     

  2. 2^n – 1 – 2² – 2³ – … – 2¹⁰⁰ = 1

     2^n = 1 + 1 +2² + 2³ + … + 2¹⁰⁰

     2^n = 2 + 2² + 2³ + … + 2¹⁰⁰

     2 . 2^n = 2.(2 + 2² + 2³ + …+ 2¹⁰⁰) 

     2.2^n = 2² + 2³ + 2⁴ + … + 2¹⁰¹
     2 . 2^n – 2^n = (2² + 2³ + 2⁴ + … + 2¹⁰¹) – (2 + 2² + 2³ + … + 2¹⁰⁰)

     2^n = 2¹⁰¹ – 2 
    Xin Hay Nhất Ạ+Sao=Cảm Ơn ạ

Leave a reply

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

About Lyla Anh