Đặt
\(A=2+2^2+2^3+...+2^{100}\)
\(2A=2^2+2^3+2^4+...+2^{101}\)
\(2A-A=2^{101}-2\)
\(A=2^{101}-2\)
Đặt A = 2 + 22 + 23 + ... + 2100
2A = 22 + 23 + 24 + ... + 2101
2A - A = (22 + 23 + 24 + ... + 2101) - (2 + 22 + 23 + ... + 2100)
A = 2101 - 2
Gọi A=2+2^2+2^3+....+2^100
Suy ra 2A= 2(2+2^2+2^3+...+2^100)
= 2^2+2^3+2^4+...+2^101
Do đó 2A-A=(2^2+2^3+2^4+...+2^100+2^101)-(2+2^2+2^3+2^4+...+2^100)
Hay A=2^2+2^3+2^4+...+2^100+2^101-2-2^2-2^3-...-2^100
=2^101-2
Vậy biểu thức đã cho sau khi rút gọn là 2^101-2
=(2+22+23+24)+(25+26+27+28)+...+(297+298+299+2100)
=2.(1+2+22+23)+25.(1+2+22+23)+...+297.(1+2+22+23)
=2.15+25.15+297.15
Tu lm tiep nha
Đặt A = 2 + 22 + 23 + ... + 2100
2A = 22 + 23 + 24 + ... + 2101
2A - A = (22 + 23 + 24 + ... + 2101) - (2 + 22 + 23 + ... + 2100)
A = 2101 - 2