2A= 1 + 1/2 + 1/4 + ... +1/128
2A= 1 + 1/2 + 1/4 + ... + 1/128 + 1/256 - 1/256
2A = 1 + A - 1/256
=> A = 1- 1/256 = 255/256
2A= 1 + 1/2 + 1/4 + ... +1/128
2A= 1 + 1/2 + 1/4 + ... + 1/128 + 1/256 - 1/256
2A = 1 + A - 1/256
=> A = 1- 1/256 = 255/256
tính nhanh ;
a) (1-1/2)x(1-1/3)x(1-1/4)x....x(1-1/2014)x(1-1/2015)
b) 1/2+1/4+1/8+....+1/256
c) 5/2+5/4+5/8+....+5/256
tính nhanh
1/2+1/4+1/8+1/16+.......+1/256+1/512
Tính nhanh
1/2 + 1/4 + 1/8 +................ + 1/128 + 1/256
Tính nhanh : 1+1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256+1/512
Tính nhanh
1/2+1/4+1/8+...+1/256
tính nhanh
a) (1-1/2)x(1-1/3)x(1-1/4)x...x(1-1/2014)x(1-1/2015).
b) 1/2 +1/4+1/8+...+1/256.
c)5/2+5/4+5/8+...+5/256
d)14,35+(13,7-13,6)x1
Tính nhanh tổng A biết :A =1/2+1/4+1/8+1/16+....+1/256+1/512
Tính nhanh
1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256
Tính nhanh:
1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256