Question

Tính nhanh:

\(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{64}+\frac{1}{128}\)

Answer 1

\(\frac{127}{128}\)nhé

Answer 2

S = \(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{64}+\frac{1}{128}\)

Sx2 = 1+ \(\frac{1}{2}+\frac{1}{4}+\frac{1}{16}+\frac{1}{64}\)

S x 2 = \(1-\frac{1}{64}\)

S x 2 = \(\frac{63}{64}\)

S = 63/64 : 2

S = 63/128

Answer 3

1/2+1/4+1/8+1/16+1/64+1/128

=1/1*2+1/2*2+1/2*4+1/2*8+1/2*16+1/2*32+1/2*64

=1/2(1+1/2+1/4+1/8+1/16+1/32+1/64)

=1/2*63/64

=63/128