Toán Lớp 6: Tính :
A=(1+2+2^2+…+2^99)-(2^100-1)
Leave a reply
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.
Toán Lớp 6: Tính :
A=(1+2+2^2+…+2^99)-(2^100-1)
Comments ( 2 )
Đặt
S=1+2+2^2+…+2^99
=>2S=(1.2)+(2.2)+(2^2. 2)+…+(2^99. 2)
=>2S=2+2^2+2^3+…+2^100
=>2S-S=(2+2^2+2^3+…+2^100)-(1+2+2^2+…+2^99)
=>S=2^100-1
=>A=S-(2^100-1)
=>A=(2^100-1)-(2^100-1)
=>A=0
Vậy A=0