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: CMR: 2+2^2+2^3+…+2^99+2^100 phải chia hết cho 3

Toán Lớp 6: CMR: 2+2^2+2^3+…+2^99+2^100 phải chia hết cho 3

Comments ( 2 )

  1. A=2 + $2^{2}$ + $2^{3}$  + … + $2^{9}$  + $2^{100}$ 
    A= 2 . (1 + 2) + $2^{3}$ (1 + 2) + …. + $2^{99}$  . (1 + 2)
    A= 2 . 3 + $2^{3}$ . 3 + … + $2^{99}$ .3
    A= 3 . (2 + $2^{3}$  + … + $2^{99}$)
    Vậy A $\vdots$ 3

  2. Lời giải và giải thích chi tiết:
    2 + 2^2 + 2^3 + …….. + 2^99 + 2^100
    = (2 + 2^2) + (2^3 + 2^4) + ………. + (2^99 + 2^100)
    = 2(1 + 2) + 2^3(1 + 2) + ……… + 2^99(1 + 2)
    = 2 . 3 + 2^3 . 3 + ………. + 2^99 . 3
    = 3 . (2 + 2^3 + ……… + 2^99) \vdots 3
    Vậy  2 + 2^2 + 2^3 + …….. + 2^99 + 2^100 \vdots 3

Leave a reply

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