Question

tinh  1/2x3+1/3x4+1/4x5+1/5x6+1/6x7+1/7x8+1/8x9+1/9x10=

 

Answer 1

Tra loi:

1/2x3+1/3x4+1/4x5+1/5x6+1/6x7+1/7x8+1/8x9

=1/2 - 1/3 + 1/3 - 1/4 +1/4 - 1/5 + 1/5 -1/6 +1/6 - 1/7 +1/7 -1/8+1/8 - 1/9

=1/2-(1/3-1/3)-(1/4-1/4)-(1/5-1/5)-(1/6-1/6)-(1/7-1/7)-(1/8-1/8)-1/9

=1/2-0-0-0-0-0-0-1/9

=1/2-1/9

=7/18

k cho minh nha!

Answer 2

thông điệp nhỏ 

hai tích nếu như ko muốn k

ai tích mình tích lại

Answer 3

cam on Mai Phuong nha!

Answer 4

2/5 moi dung

Answer 5

a=1/2 - 1/3 + 1/3 - 1/4 + 1/4 - 1/5 + 1/5 - 1/6

a=1/2 - 1/6

a=3/6 - 1/6

a= 2/6

a=1/3