Question

tính  A = 1/2 +1/2^{2 +} ..............+1/2²⁰¹⁶

 như này  : / là phần nha

 

Answer 1

A = 1/2 +1/2^{2 +} ...+1/2²⁰¹⁶

Ta có:

2A = 1 + 1/2 + ..............+1/2²⁰¹⁶

A   = 1/2 +1/2^{2 +} ...+1/2²⁰¹⁶

2A - A = A = 1 - 1/2²⁰¹⁶

Answer 2

A=1/2+1/2²+...............+1/2²⁰¹⁶

2A=1+1/2+.................+1/2²⁰¹⁵

2A-A=(1+1/2+........+1/2²⁰¹⁵)-(1/2+1/2²+..........+1/2²⁰¹⁶)

A=1-1/2²⁰¹⁶

A=2²⁰¹⁶-1/2²⁰¹⁶

.

Answer 3

A=1/2+1/2²+...............+1/2²⁰¹⁶

2A=1+1/2+.................+1/2²⁰¹⁵

2A-A=(1+1/2+........+1/2²⁰¹⁵)-(1/2+1/2²+..........+1/2²⁰¹⁶)

A=1-1/2²⁰¹⁶

A=2²⁰¹⁶-1/2²⁰¹⁶

Answer 4

A=1/2+1/2²+...............+1/2²⁰¹⁶

2A=1+1/2+.................+1/2²⁰¹⁵

2A-A=(1+1/2+........+1/2²⁰¹⁵)-(1/2+1/2²+..........+1/2²⁰¹⁶)

A=1-1/2²⁰¹⁶

A=2²⁰¹⁶-1/2²⁰¹⁶