\(\Rightarrow C=\frac{10}{5}\left(\frac{1}{7.12}+\frac{1}{12.17}+\frac{1}{17.22}+...+\frac{1}{502.507}\right)\)
\(\Rightarrow C=2.\left(\frac{1}{7}-\frac{1}{12}+\frac{1}{12}-\frac{1}{17}+....+\frac{1}{507}-\frac{1}{507}\right)\)
\(\Rightarrow C=2.\left(\frac{1}{7}-\frac{1}{507}\right)=2.\frac{1}{7}-2.\frac{1}{507}=\frac{2}{7}-\frac{2}{507}\)
K=10/7.12+10/12.17+10/17.22+...+10/502.507
Ai nhanh mk tik
tính:
B= 10/7.12+10/12.17+10/17.22+.......+10/502.507
Tính : \(N=2015+\frac{10}{2.7}+\frac{10}{7.12}+\frac{10}{12.17}+\frac{10.}{17.22}\)
Tính
A= 10/7.12 + 10/12.17 + 10/17.22 + .... + 10/502.507
B= 1/6.10 + 1/10.14 + 1/14.18 +.... + 1/ 402.406
Nhanhh nhaaa iuuu iuuu
1) Tính nhanh
\(\frac{5}{2.7}+\frac{5}{7.12}+\frac{5}{12.17}+\frac{5}{17.22}+\frac{5}{22.27}+\frac{5}{27.32}+\frac{5}{32.37}\)
Tinh gia tri cac bieu thuc sau
B= \(\frac{10}{2.7}+\frac{10}{7.12}+...+\frac{10}{502.507}\)
C= \(\frac{1}{18}+\frac{1}{54}+\frac{1}{108}+...+\frac{1}{990}\)
\(\frac{5}{2.7}+\frac{5}{7.12}+\frac{5}{12.17}+\frac{5}{17.22}+\frac{5}{22.29}=?\)
Tính nhanh:
a) \(A=\frac{3}{5.8}\)+ \(\frac{3}{8.11}\)+ \(\frac{3}{11.14}\)+ ... + \(\frac{3}{2006.2009}\)
b) \(B=\frac{1}{6.10}\)+ \(\frac{1}{10.14}\)+ \(\frac{1}{14.18}\)+...+ \(\frac{1}{402.406}\)
c) \(C=\frac{10}{7.12}\)+\(\frac{10}{12.17}\)+\(\frac{10}{17.22}\)+...+\(\frac{10}{502.507}\)
d) \(D=\frac{4}{8.13}\)+\(\frac{4}{13.18}\)+\(\frac{4}{18.23}\)+...+\(\frac{4}{253.258}\)
Tính:A=1/7.12+1/12.17+1/17.22+...+1/52.57
B=10/8.13+10/13.18+10/18.23+...+10/253.258
