Question

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

A=?

Answer 1

\(A=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}\)

\(A=\frac{32+16+8+4+2+1}{64}\)

\(A=\frac{63}{64}\)

Chúc bạn học tốt và tíck cho mìk vs nha!

Answer 2

cach 1

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

ta thấy:1/2=1-1/2; 1/4 = 1/2 - 1/4;... ;1/64 = 1/32 - 1/64

A = 1-1/2+1/2-1/4+1/4-1/8+1/8-1/16+1/16-1/32+1/32-1/64

A=1-1/64

A=63/64

cách 2

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

A x 2=1+1/2+1/4+1/8+1/16+1/32

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

A x 2 = 1-1/64

A x 2 =63/64

A       =63/64 : 2

A        = 63/128