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: Tính tổng A biết A=2+2^2+2^3+…+2^99+2^100 Hộ cái này nha!!!

Toán Lớp 6: Tính tổng A biết A=2+2^2+2^3+…+2^99+2^100
Hộ cái này nha!!!

Comments ( 2 )

  1. Tham khảo:
    A = 2 + 2^2 + 2^3 + … + 2^(99) + 2^(100)
    2A = 2^2 + 2^3 + 2^4 + … + 2^(100) + 2^(101)
    2A – A = ( 2^2 + 2^3 + 2^4 + … + 2^(100) + 2^(101) ) – ( 2 + 2^2 + 2^3 + … + 2^(99) + 2^(100) )
    A = 2^(101) – 2
    #IE

  2. A = 2 + 2^2 + 2^3 + … + 2^99 + 2^100
    => 2A = 2^2 + 2^3 + 2^4 + … + 2^100 + 2^101
    => 2A – A  = ( 2^2 + 2^3 + 2^4 + … + 2^100 + 2^101 ) – ( 2 + 2^2 + 2^3 + … + 2^99 + 2^100 )
    => A = 2^101 – 2
    Vậy A = 2^101 – 2
    #dtkc
     

Leave a reply

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

About Thanh Thu