Question

tính tổng 1+1/2+1/4+1/8+1/16

                                         Các bạn ơi giúp mình nhé !

Answer 1

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

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

A x 2 = 1-  A - 1/16

A x 2 - A = 1 - 1/16

A           =   1 - 1/16

A           = 15/16

Answer 2

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

Ax2=(1+1/2+1/4+1/8+1/16)x2

Ax2= 2+1+1/2+1/4+1/8 

Mà A= Ax2-A

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

A=2- 1/16

A= 31/16

Answer 3

Ta có : A = 1 + 1/2 + 1/4 + 1/8 + 1/16

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

2A = 1-  A - 1/16

2A - A = 1 - 1/16

A           =   1 - 1/16

A           = 15/16

Answer 4

Ta có : A = 1 + 1/2 + 1/4 + 1/8 + 1/16

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

2A = 1-  A - 1/16

2A - A = 1 - 1/16

A           =   1 - 1/16

A           = 15/16