= \(\frac{1}{3.6}-\frac{1}{6.9}+\frac{1}{6.9}-\frac{1}{9.12}+....+\frac{1}{23.26}-\frac{1}{26.29}\)
= \(\frac{1}{3.6}-\frac{1}{26.29}\)
= \(\frac{23}{26}\).
H=\(\frac{1\cdot2\cdot3+2\cdot4\cdot6+3\cdot6\cdot9+5\cdot10\cdot15}{1\cdot3\cdot6+2\cdot6\cdot12+3\cdot9\cdot18+5\cdot15\cdot30}\)= ?
\(a=\frac{2\cdot9\cdot8+3\cdot12\cdot10+4\cdot15\cdot12+...+98\cdot297\cdot200}{23\cdot4+3\cdot4\cdot5+4\cdot5\cdot6+...+98\cdot99\cdot100}\)
Tính a2
Tính tổng: \(\frac{1}{5\cdot6}+\frac{1}{10\cdot9}+\frac{1}{15\cdot12}+.......+\frac{1}{3350\cdot2013}\)
\(\frac{1}{6\cdot10}+\frac{1}{7\cdot9}+\frac{1}{8\cdot8}+\frac{1}{9\cdot7}+\frac{1}{10\cdot6}\)
Tính:
\(B=\frac{18^6\cdot2^{12}\cdot4^3\cdot9^3}{16^3\cdot6^9\cdot27^3}\)
Giúp mình với!
CHO \(a=\frac{2\cdot9\cdot8+3\cdot12\cdot10+4\cdot15\cdot12+...+98\cdot297\cdot200}{23\cdot4+3\cdot4\cdot5+4\cdot5\cdot6+...+98\cdot99\cdot100}\)
Tính a2
\(\frac{2\cdot4\cdot10+4\cdot6\cdot8+14\cdot16\cdot20}{3\cdot6\cdot15+6\cdot9\cdot12+21\cdot24\cdot30}\)
CÁC BN LÀM HỘ MK NHÉ
a)A=\(\frac{1}{1\cdot3\cdot5}+\frac{1}{3\cdot5\cdot7}+\frac{1}{5\cdot7\cdot9}+...+\frac{1}{25\cdot27\cdot29}\)
b)\(\left(\frac{1}{1\cdot101}+\frac{1}{2\cdot102}+...+\frac{1}{10\cdot110}\right)\cdot x=\frac{1}{1.11}+\frac{1}{2\cdot12}+...+\frac{1}{100\cdot110}\)
\(A=\frac{7}{10\cdot11}+\frac{7}{11\cdot12}+\frac{7}{12\cdot13}+...+\frac{7}{69\cdot70}\)
\(B=\frac{1}{25\cdot27}+\frac{1}{27\cdot29}+\frac{1}{29\cdot30}+...+\frac{1}{73\cdot75}\)
\(C=\frac{4}{2\cdot4}+\frac{4}{4\cdot6}+\frac{4}{6\cdot8}+...3+\frac{4}{2008\cdot2010}\)
