C=\(\frac{3}{4}\)x\(\frac{8}{9}\)x\(\frac{15}{16}\)x .............x\(\frac{9999}{10000}\)
D=\(\frac{1}{500}+\frac{3}{500}+\frac{5}{500}+.........+\frac{95}{500}+\frac{97}{500}+\frac{99}{500}\)
E=1\(\frac{1}{3}\)x 1\(\frac{1}{8}\)x 1 \(\frac{1}{15}\)x 1\(\frac{1}{24}\)x.......x 1\(\frac{1}{99}\)
F=\(\frac{4}{1x3}+\frac{4}{3x5}+\frac{4}{5x7}+\frac{4}{7x9}+..........+\frac{4}{17x19}+\frac{4}{19x21}\)
G=\(\frac{1}{11x16}+\frac{1}{16x21}+\frac{1}{21x26}+.....+\frac{1}{56x61}+\frac{1}{66x61}\)
Mọi người giúp mình nha . mai mik phải nộp rùi.thank mọi người nhìu lắm
\(C=\frac{3}{4}x\frac{8}{9}x\frac{15}{16}x...x\frac{9999}{10000}\)
\(C=\frac{3}{4}x\frac{4x2}{3x3}x\frac{3x5}{2x8}x...x\frac{99x101}{100x100}\)
\(C=...\) ( Tự làm tiếp )
\(E=1\frac{1}{3}x1\frac{1}{8}x1\frac{1}{15}x1\frac{1}{24}x...x1\frac{1}{99}\)
\(E=\frac{4}{3}x\frac{9}{8}x\frac{16}{15}x\frac{25}{24}x...x\frac{100}{99}\)
\(E=....\)( tương tự câu C )
\(F=\frac{4}{1x3}+\frac{4}{3x5}+\frac{4}{5x7}+\frac{4}{7x9}+...+\frac{4}{17x19}+\frac{4}{19x21}\)
\(Fx\frac{1}{2}\)\(=\frac{1}{1}-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}+...+\frac{1}{19}-\frac{1}{21}\)
\(Fx\frac{1}{2}=\frac{1}{1}-\frac{1}{21}\)
\(F=\frac{20}{21}:2=\frac{20}{42}=\frac{5}{6}\)
