Đặt A = 3100 - 398 + 396 - 394 + ...+ 32 - 1
=> 32.A = 3102 - 3100 + 398 - 396 + ...+ 34 - 32
=> 9.A + A = 3102 - 1
10.A = 3102 - 1
\(A=\frac{3^{102}-1}{10}\)
A.100-99+98+97+96+95+...+4-3+2-1
B.100-98+96-94+...+4-2
100+98+96+94+...+2-97-75-...-3-1
100 + 98 + 96 + 94 + .... + 2 -1 -3 -5 - .... -97
100+98+96+94+...-4-2+99-97-95-...-3-1=?
A=100 - 99-98-97+ 96-95-94 - 93 + ............... + 4-3-2-1 = ?
tinh gia tri bieu thuc A =100+98+96+94+...+2-1-3-5-7-9-...-95-97
Tính :2^100 - 2^99 - 2^98 - 2^97 - 2^96 - 2^95 - 2^94 - ........- 2^3 - 2^2 -2 - 1
Tìm x
a ) 1 + 2+ 3+ ... + x = 325
b ) 100 - 98 + 96 - 94 ... +4 - 2 = ?
Tính nhanh
a, 100-98+96-94+......+4-2+1
b,[1-1/2] . [1-1/3] . [1-1/4] . ...... . [1-1/2018]
c,[1+1/2] . [1+1/3] . [1+1/4]. ..... .[1+1/2017]
