Đặt A = 2^0 + 2^1 + 2^2 + ... + 2^100
2A = 2^1 + 2^2 + 2^3 + ... + 2^101
2A - A = (2^1 + 2^2 + 2^3 + ... + 2^101) - (2^0 + 2^1 + 2^2 + ... + 2^100)
A = 2^101 - 2^0
A = 2^101 - 1
Đặt A=20+21+22+...+2100
2A=21+22+23+...+2101
-
A=20+21+22+...+2100
-----------------------------------------
=>2A-A=2101-20
=>A=2101-1
Chúc bạn học giỏi nha!!!
K cho mik vs nhé
Ta có: 2^0+2^1+...+2^100
Đặt C = 2^0+2^1+2^2+...+2^100
=> 2C = 2^1+2^2+2^3+....+2^101
=>2C-C = (2^1+2^2+2^3+...+2^101) - (2^0+2^1+....+2^100)
=> C = 2^101 - 2^0 ( Mà 2^0 = 1)
Vậy C = 2^101 - 1