Question

        1          -          1            -              1                   -                1

2000*1999     1999*1998         1998*1997         ………….             1*2

Answer 1

bó tay nhé bạn

Answer 2

\(\frac{1}{2000.1999}-\frac{1}{1999.1998}-...-\frac{1}{1.2}\)

\(=-\left(\frac{1}{1.2}+...+\frac{1}{1998.1999}+\frac{1}{1999.200}\right)\)

\(=-\left(\frac{1}{1}-\frac{1}{2}+...+\frac{1}{1998}-\frac{1}{1999}+\frac{1}{1999}-\frac{1}{2000}\right)\)

\(=-\left(1-\frac{1}{2000}\right)\)

\(=\frac{-1999}{2000}\)

Answer 3

1/2000*1999-1/1999*1998-1/1998*1/1997-.......-1/1*2

=1/2000-1

=-1999/2000

Answer 4

nhầm, bạn tách ra ntn rồi tính nha:

\(\frac{1}{2000.1999}-\left(\frac{1}{1999.1998}+...+\frac{1}{1.2}\right)\)