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: chứng tỏ rằng: 2^1+2^2+-.2^50 chia hết cho 3

Toán Lớp 6: chứng tỏ rằng:
2^1+2^2+…..2^50 chia hết cho 3

Comments ( 2 )

  1. $Ta$ $có :$
    2^1 + 2^2 + … + 2^{50}
    = ( 2 + 2^2 ) + …. + ( 2^{49} + 2^{50} )
    = 2. ( 1 + 2 ) + … + 2^{49}. ( 1 + 2 )
    = 2. 3 + … + 2^{49}. 3
    = 3. ( 2 + … + 2^{49} )    \vdots 3 ( đpcm )

  2. Giải đáp:
    $2^{1}$ + $2^{2}$ + …. +$2^{50}$
    =($2^{1}$ + $2^{2}$)+…+($2^{49}$+ $2^{50}$ )
    =2(1+2)+…+$2^{49}$ (1+2)
    =2.3+…+$2^{49}$ .3
    =3(2+..+$2^{49}$ )
    Vì 3⁝3
    Nên $2^{1}$ + $2^{2}$ + …. + $2^{50}$ ⁝ 3
    $@Lun$
     

Leave a reply

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