Đặt A = 1 + 1/2 + 1/4 + ... + 1/64
2A = 1 + 1/2 + 1/4 + ... + 1/32
2A - A = ( 1 + 1/2 + ... + 1/32 ) - ( 1 + 1/2 + ... + 1/64 )
A = 1 - 1/64
A = 63/64
1+1+2+2+4+4+8+8+16+16+32+32+64+64=?
bk nha@ >_0
1/2 + 1/4+1/8+1/16+1/32+1/64
B=1/2+1/4+1/8+1/16+1/32+1/64
1/2+1/4+1/8+1/16+1/32+1/64
1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64
1/2+1/4+1/8+1/16+1/32+1/64=
1/2+1/4+1/8+1/16+1/32+1/64
Tính nhanh :
1/2+1/4+1/8+1/16+1/32+1/64
C = 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128
