Question

A = 1/1 x 2 + 1/2 x 3 + 1/3 x 4 +...+ 1/2014 x 2015

A = ?

/ có nghĩa là phần

Answer 1

A = 1/1.2 + 1/2.3 + 1/3.4 +.....+1/2014.2015

A = 1/1+( -1/2 + 1/2)+ (-1/3 +1/3) +( -1/4 + 1/4)+ -1/5 +............... 1/2014 + -1/ 2015

A = 1/1 + -1 /2015 

A = 2015/2015 + -1 /2015 = 2014/2015.

Answer 2

ko biết mk ko giỏi lắm

Answer 3

BÀi giải

A= 1/1 x 2+ 1/2 x 3+1/3 x 4 +........+ 1/2014 x 2015

A= 1/1 - 1/2 + 1/2 - 1/3 +1/3 - 1/4 + 1/4 -........+ 1/2014 - 1/2015

A= 1/1 - 1/2015

A=2015/2015 - 1/2015

A= 2014/2015

Answer 4

A = 1/1 x 2 +1/2 x 3 + 1/3 x 4 + ... + 1/2014 x 2015

A = 1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + ... + 1/2014 - 1/2015

A = 1 - 1/2015

A = 2014/2015

Answer 5

\(A=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-..........+\frac{1}{2014}-\frac{1}{2015}\)

\(A=\frac{1}{1}-\frac{1}{2015}=\frac{2014}{2015}\)