1/6+1/66+1/176+....+1/496.501

=1/1.6+1/6.11+1/11.16+....+1/496.501

=(1/5).(5/1.6+5/6.11+5/11.16+....+5/496.501)

=(1/5).(1-1/6+1/6-1/11+1/11-1/16+...+1/496-1/501)

=(1/5).(1-1/501)

=1/5 . 500/501

=100/501 

nen bo buoc 2 di

\(S=\frac{1}{1\cdot6}+\frac{1}{6\cdot11}+\frac{1}{11\cdot16}+...+\frac{1}{496\cdot501}\)

\(S=\frac{1}{5}\left(1-\frac{1}{6}+\frac{1}{6}-\frac{1}{11}+...+\frac{1}{496}-\frac{1}{501}\right)\)

\(S=\frac{1}{5}\left(1-\frac{1}{501}\right)\)

\(S=\frac{1}{5}\cdot\frac{500}{501}\)

\(S=\frac{100}{501}\)

\(\frac{1}{1.6}+\frac{1}{6.11}+\frac{1}{11.16}+...+\frac{1}{496.501}\)

\(=\frac{1}{5}\left(1-\frac{1}{6}+\frac{1}{6}-\frac{1}{11}+...+\frac{1}{496}-\frac{1}{501}\right)\)

\(=\frac{1}{5}\left(1-\frac{1}{501}\right)=\frac{1}{5}\cdot\frac{500}{501}=\frac{100}{501}\)

1/5 bạn lấy ở đâu

,r5 ơi mẹ ghi zậy ai hiểu chết liền

Nghĩa là dzậy nè:1/1x6 + 1/6x11 + 1/11x16 + ..... +1/491x496 + 1/496x501

Bạn đỗ trần hải nam nói đúng rồi đó mà sao bn ko giải giúp mình luôn đi

1/6+1/66+1/176+....+1/496.501

=1/1.6+1/6.11+1/11.16+....+1/496.501

=(1/5).(5/1.6+5/6.11+5/11.16+....+5/496.501)

=(1/5).(1-1/6+1/6-1/11+1/11-1/16+...+1/496-1/501)

=(1/5).(1-1/501)

=1/5 . 500/501

=100/501

Ta có: 1/6+1/66+1/176+1/336+...+1/496.501

         =1/1.6+1/6.11+1/11.16+1/16.21+...+1/496.501

         =1/5.(5/1.6+5/6.11+5/11.16+5/16.21+...+5/496.501)

         =1/5.(1-1/6+1/6-1/11+1/11-1/16+1/16-1/21+...+1/496-1/501)

         =1/5.(1-1/501)

         =1/5.500/501

         =100/501

đúng không trần hương giang