Question

1/1x2+1/2x3+1/3x4+...+1/2013x2014+1/2014x2015

Answer 1

1/1*2 + 1/2*3 + 1/3*4 + ... + 1/2013*2014 + 1/2014*2015

= 1 -1/2 + 1/2 - 1/3 + 1/3 - 1/4 + ... + 1/2013 - 1/2014 + 1/2014 - 1/2015

=1-1/2015

=2014/2015

Answer 2

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

=1-1/2015

=2014/2015

Answer 3

đây là toán lớp 5 mà