Đặt \(S=2^{100}-2^{99}-2^{98}-...-2^2-2^1-1.\)
\(\Rightarrow2S=2^{101}-2^{100}-2^{99}-...-2^3-2^2-2\)
\(\Rightarrow2S-S=S=\left(2^{101}-2^{100}-...-2^2-2\right)-\left(2^{100}-2^{99}-...-2^1-1\right)\)
\(\Rightarrow S=2^{101}+1\)
B=3^100-3^99-3^98-..-3-1
B=3^100-(3^99+3^98+...+3+1)
ta có:M=3^99+3^98+..+3+1
3M=3^100+3^98+...+3^2+3
2M=3M-M=3^100+3^99+3^98+...+3^2+3-3^99+3^98+...+1
2M=3^100-1
=>B=3^100-3^100+1:2
B=0+1/2
B=1/2
A = 2^100 - 2^99 - 2^98 -...- 2 - 1
= 2^100 - ( 2^99 + 2^98 +...+ 2 + 1 )
= ??????
20^5-5^10:100^5
B=3^100-3^99+3^98-.........+3^2-3+1
D=2^100-2^99+2^98-.........+2^2-2+1
C= 1/100 -1/100×99 -1/99×98 -1/98×97-...-1/3×2 - 1/2×1
A = 1 . 2 + 2 . 3 + 3 . 4 + ......... + 98 . 99 / 1 + ( 1 + 2 ) + ( 1 + 2 + 3 ) + ........... + ( 1 + 2 + 3 + ...... + 98 )
B = ( 1 / 51 . 52 ) + 1 / 52 . 53 + ...... + 1 / 100 . 101 ) : ( 1 / 1 . 2 + 1 / 2 . 3 + ........ + 1 / 99 . 100 + 1 / 100 . 101
101+100+99+98+...+3+2+1/101-100+99-98+...+3-2+1
B=(101+100+99+98+.....+3+2+1) / (101-100+99-98+.......+3-2+1)
B=(101+100+99+98+.....+3+2+1) / (101-100+99-98+.......+3-2+1)
A=101+100+99+98+...+3+2+1/101-100+99-98+...+3-2+1
Tính nhanh
A= 1-2+3-4+....+99-100
B= 1-2-3+4+5-6-7+....+97-98-99+100
C= 2 mũ 100 - 2 mũ 99 - 2 mũ 98 - 2 mũ 2 - 2 -1