=1-1/2+1/2-1/3+...+1/999-1/1000+1
=1-1/100+1
=199/100
=1-1/2+1/2-1/3+...+1/999-1/1000+1
=1-1/100+1
=199/100
\(\frac{1}{1\cdot2}\)+\(\frac{1}{2\cdot3}\)+\(\frac{1}{3\cdot4}\)+...................+\(\frac{1}{999\cdot1000}\)+1
\(\frac{1}{1\cdot2}+\)\(\frac{1}{2\cdot3}+\)\(\frac{1}{3\cdot4}+........\)\(\frac{1}{998\cdot999}+\)\(\frac{1}{999\cdot1000}=\)
Tính tổng sau :
\(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+...........+\frac{1}{999\cdot1000}+1\)
Dấu chấm ở trên là dấu nhân
Tính tổng :
\(\frac{1}{1\cdot2}\)+ \(\frac{1}{2\cdot3}\)+\(\frac{1}{3\cdot4}\)+.........+\(\frac{1}{999\cdot1000}\)+ 1
1.
a) \(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+....+\frac{1}{2017\cdot1018}\)
b) \(\frac{2}{1\cdot2}+\frac{2}{2\cdot3}+\frac{2}{3\cdot4}+....+\frac{2}{2017\cdot2018}+\frac{2}{2018\cdot2019}\)
c) \(\frac{4}{1\cdot2}+\frac{4}{2\cdot3}+\frac{4}{3\cdot4}+......+\frac{4}{1999\cdot2000}\)
********Lưu ý :
1) Các dấu chấm ở phân số là dấu nhân ạ..!!!
2) Trình bày rõ ràng giúp mk với ạ..!!!
(\(\frac{1}{1\cdot2}+\frac{1}{2\cdot3} +\frac{1}{3\cdot4}+\frac{1}{5\cdot6}\))*10-x=0
\(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+\frac{1}{5\cdot6}=\)
k mik mik k lại
\(A=\frac{1\cdot2}{2\cdot2}\cdot\frac{2\cdot3}{3\cdot3}\cdot\frac{3\cdot4}{4\cdot4}\cdot\frac{4\cdot5}{5\cdot5}\cdot.................\cdot\frac{2012\cdot2013}{2013\cdot2013}\)với
\(B=\frac{2012\cdot2013-2012\cdot2012}{2012\cdot2011+2012\cdot2}\)
1) Tính
a)\(\frac{13}{15}+\frac{13}{35}+\frac{13}{63}+\frac{13}{99}\)
b)\(\left(\frac{15}{1\cdot2\cdot3}+\frac{15}{2\cdot3\cdot4}+\frac{15}{3\cdot4\cdot5}+.....+\frac{15}{18\cdot19\cdot20}\right)\cdot x=1\)