Các bn giúp mik bài tập này vs chiều nay mik phải nộp rồi . Các bn làm đc phần nào thì lm nhé .Thank nhiều
Bài 1 :Tính Nhanh
a) \(\frac{-5}{11}.\left(\frac{2222}{1010}+\frac{2222}{1515}+\frac{2222}{2121}+\frac{2222}{2828}+\frac{2222}{3636}+\frac{2222}{4545}\right)\)
b) \(\frac{1}{100}-\frac{1}{50.48}-\frac{1}{48.46}-...-\frac{1}{4.2}\)
c) \(\frac{\frac{1}{2}-\frac{1}{3}}{\frac{1}{3}-\frac{1}{4}}.\frac{\frac{1}{4}-\frac{1}{5}}{\frac{1}{5}-\frac{1}{6}}.....\frac{\frac{1}{98}-\frac{1}{99}}{\frac{1}{99}-\frac{1}{100}}\)
CMR
\(\frac{1}{5}< \frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{98}-\frac{1}{99}< \frac{2}{5}\)\(\frac{2}{5}\)
CTR: \(\frac{1}{5}<\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}+\frac{1}{6}-...+\frac{1}{98}-\frac{1}{99}<\frac{2}{5}\)
CTR: \(\frac{1}{5}<\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}+\frac{1}{6}-...+\frac{1}{98}-\frac{1}{99}<\frac{2}{5}\)
Chứng minh rằng
a) \(\frac{1}{5}<\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{98}-\frac{1}{99}<\frac{2}{5}\)
b) \(\frac{1}{15}<\frac{1}{2}.\frac{3}{4}.\frac{5}{6}...\frac{99}{100}<\frac{1}{10}\)
1. Tính tích N=\(\frac{1}{2}.\frac{-2}{3}.\frac{3}{4}.\frac{-4}{5}.\frac{5}{6}.\frac{-6}{7}.......\frac{-98}{99}.\frac{99}{100}\)
Cho A=\(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{98}-\frac{1}{99}\)
CMR:0,2<A<0,4
Tính :\(A=\frac{5}{1\times2}+\frac{5}{2\times3}+\frac{5}{3\times4}+....+\frac{5}{99\times100}\)Ai nhanh mik tick nha^_-
1\(\frac{1}{30}:\left(24\frac{1}{6}-24\frac{1}{5}\right)-\)\(1\frac{1}{\frac{2}{4.x-\frac{1}{2}}}-\frac{3}{4}\)=\(\left(-1\frac{1}{15}\right):\left(8\frac{1}{5}-8\frac{1}{3}\right)\)ai nhanh mik tick