1/2 + 1/4 + 1/8+....+1/1024
= 1/2 (1/2 + 1/4 + 1/8+....+1/1024)
= 1/4 + 1/8 +....+1/2048
= (1/2 + 1/4 + 1/8+....+1/1024) - (1/4 + 1/8 +....+1/2048)
= 1/2- 1/2048
= 1023/2048
1/2 + 1/4 + 1/8+....+1/1024
= 1/2 (1/2 + 1/4 + 1/8+....+1/1024)
= 1/4 + 1/8 +....+1/2048
= (1/2 + 1/4 + 1/8+....+1/1024) - (1/4 + 1/8 +....+1/2048)
= 1/2- 1/2048
= 1023/2048
Tính nhanh
1) 101-98+...+11-8+5-2
2) 1000-996+992-988+...+8-4
3) 1024-1022+...+4-2
4) 311-305+...+11-5
5) 162-157+...+12-7
6) 1051-1049+...+15-13
Tính nhanh
1/2 + 1/4 + 1/8 + 0 + ... + 1/1024
1/2 - 1/4 - 1/8 - .... - 1/1024 tính
Tính S= 1 + 1/2 + 1/4 + 1/8 + .... + 1/1024
Tính hợp lý:1+1/2+1/4+1/8+...+1/1024= ?
Tính nhanh
1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42
tính nhanh
1+1/2+1/4+1/8+...+1/1024
Tính :
A= 1+1/2+1/4+1/8+...+1/1024
tính nhanh S=1+1/2+1/4+1/8+...+1/1024