Cho \(A=\frac{1}{2}\times\frac{3}{4}\times\frac{5}{6}\times...\times\frac{199}{200}\)và chứng minh \(A^2< \frac{1}{201}\)
Chứng minh rằng \(\frac{1}{2}\times\frac{3}{4}\times\frac{5}{6}\times\frac{7}{8}\times...\times\frac{99}{100}< 0,01\)
Chứng minh rằng:\(\frac{-1}{2}\times\frac{-3}{4}\times\frac{-5}{6}\times...\times\frac{-399}{400}< \frac{1}{20}\)
\(\frac{1}{3}\times\frac{2}{5}\times\frac{3}{7}\times\frac{4}{9}\times\frac{5}{11}\times\frac{6}{15}\times\frac{7}{15}\times\frac{8}{15}\times\frac{9}{19}\times\frac{10}{21}\times\frac{11}{32}\times\frac{12}{25}\times\left\{\frac{126}{252}-\frac{2}{4}\right\}\)
1. Tính nhanh:
a.\(\frac{17}{13}\times\frac{7}{15}-\frac{5}{12}\times\frac{21}{39}+\frac{49}{91}\times\frac{8}{15}\)
b.\(\left(\frac{12}{199}+\frac{23}{200}-\frac{34}{201}\right)\times\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\)
2. So sánh:
a. 3200và2300
b. 7150và3775
c.\(\frac{201201}{202202}\)và\(\frac{201201201}{202202202}\)
\(A=\left(1\frac{1}{6}\times\frac{6}{7}\times6:\frac{3}{5}\right):\left(4\frac{1}{5}\times\frac{10}{11}+5\frac{2}{10}\right)\)
\(B=1\frac{13}{15}\times25\%\times3+\left(\frac{8}{15}-\frac{79}{60}\right):1\frac{23}{4}\)
\(C=\frac{123}{4567}\times\frac{1}{8}+\frac{123}{4567}\times\frac{1}{2}-\frac{123}{4567}\times\frac{13}{8}\)
\(D=\frac{10\frac{1}{3}\times\left(24\frac{1}{2}-15\frac{6}{7}\right)-\frac{12}{11}\times\left(\frac{10}{3}-1,75\right)}{\left(\frac{5}{9}-0,25\right)\times\frac{60}{11}+194\frac{8}{99}}\)
cho A=\(\frac{1}{2}\times\frac{3}{4}\times.....\times\frac{399}{400}\)Chứng minh A<\(\frac{1}{20}\)
Các bạn ơi giúp mình giải bài này với:
Đề bài:Cho A=\((\frac{1}{2^2}-)\times(\frac{1}{2^2}-1)\times(\frac{1}{4^2}-1)\times...(\frac{1}{100^2}-1)\)
TÍNH : E=\(\frac{2^2}{3}\times\frac{3^2}{8}\times\frac{4^2}{15}\times\frac{5^2}{24}\times\frac{6^2}{35}\times\frac{7^2}{48}\times\frac{8^2}{63}\times\frac{9^2}{80}\)