Tính nhanh: 3 + 6 + 12 + 24 + ... + 1536.
Giải thích
S=3+6+12+24+48+...+1536
2S=6+12+24+48+...+3072
2S‒S= (6+12+24+48+...+3072) ‒ (3+6+12+24+48+...+1536)
S = 3072 ‒ 3
S=3069
Vậy S=3069.
S=3+6+12+24+48+...+1536
2S=6+12+24+48+...+3072
2S‒S= (6+12+24+48+...+3072) ‒ (3+6+12+24+48+...+1536)
S = 3072 ‒ 3
S=3069
Vậy S=3069.