\(\frac{127}{128}\times x=1\)
\(\Rightarrow x=\frac{128}{127}\)
minh muon ban trinh bay ro rang hon
X*[1/2+1/4+1/8+1/16+1/32+1/64+1/128]=127/128
1. tinh nhanh: 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128
2. tim x: ( x + 1/2 ) + ( x +1/4 ) + ( x + 1/8 ) + ( x + 1/16 ) = 1
tính nhanh p/s 1+ 5/4 + 5/8 + 5/16 + 5/32 + 5/64
b) 1/3 +1/9 + 1/27 + 1/81 +...........+ 1/59049
c) 3/2 + 3/8 + 3/32 +3/128 + 3/512
d) 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 giúp mình với 
C = 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128
1/2+1/4+1/8+1/16+1/32+1/64+1/128
1/2+1/4+1/8+1/16+1/32+1/64+1/128
1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/64 + 1/128
1/2+1/4+1/8+1/16+1/32+1/64+1/128 = ?
1\2+1\4+1\8+1\16+1\32+1\64+1\128
