Question

[Nguyễn Thị Mai Uyên]

tinh tong S , biet : S = \(\frac{1}{1x2}+\frac{1}{2x3}+\frac{1}{3x4}+.......+\frac{1}{2010x2011}\)

k mk 3 cai nha mk k lai cho

Answer 1

[ST]

\(S=\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{2010.2011}\)

\(S=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{2010}-\frac{1}{2011}\)

\(S=1-\frac{1}{2011}\)

\(S=\frac{2010}{2011}\)

Answer 2

[NGYUN1234]