1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90+109/110= 1 - 1/2 + 1 - 1/6 + 1 - 1/12 .....+1 - 1/110= 10 - ( 1/2 + 1/6 + ...+ 1/110) = 10 - ( 1 - 1/ 2+ 1/2 - 1/ 3+ 1/3 - 1/4 ....+ 1/10 - 1/11)= 10 - (1 - 1/11)= 10 - 10/11 = 100/11
= 100/11 nha bạn
k cho minh nha
chuc ban hoc tot
= \(\frac{100}{11}\)
k cho mik nha
thank you
= (1-1/2) + (1-1/6) + (1-1/12) +(1-1/20)+ (1-1/30) + (1-1/42) + (1-1/56) +(1-1/72)+(1-1/90)+(1-1/110)
= (1+1+1+1+1+1+1+1+1+1) - (1/2 +1/6 +1/12+...+1/90+1/110)
=10-(1/1x2+ 1/2x3 +1/3x4 + ... +1/ 9x10 +1/10x11)
=10- ( 1-1/2 +1/2-1/3+1/3-1/4+1/4 + ...+1/9-1/10 +1/10-1/11)
=10-(1-1/11)
=10-10/11
=100/11
Nếu đúng thì bạn k đi nà. (đúng rùi)(^_^)
câu trả lời=100/11 bởi vì bạn này mình làm rồi
nhớ k cho mình nhé,cảm ơn các ban
\(\frac{1}{2}+\frac{5}{6}+\frac{11}{12}+\frac{19}{20}+...+\frac{89}{90}+\frac{109}{110}\)
\(=1-\frac{1}{2}+1-\frac{1}{6}+1-\frac{1}{12}+1-\frac{1}{20}+...+1-\frac{1}{90}+1-\frac{1}{110}\)
\(=10-\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{90}+\frac{1}{110}\right)\)
\(=10-\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{9.10}+\frac{1}{10.11}\right)\)
\(=10-\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+....+\frac{1}{9}-\frac{1}{10}+\frac{1}{10}-\frac{1}{11}\right)\)
\(=10-\left(1-\frac{1}{11}\right)\)
\(=\frac{100}{11}\)
