\(A=\frac{1}{4}.\frac{3}{6}.\frac{5}{8}....\frac{43}{46}.\frac{45}{48}\)
\(B=\frac{2}{5}.\frac{4}{7}.\frac{6}{9}....\frac{44}{47}.\frac{46}{49}\)
a) So sánh A và B
b) Chứng minh A<133
\(A=\frac{1}{4}.\frac{3}{6}.\frac{5}{8}....\frac{43}{46}.\frac{45}{48}\)
\(B=\frac{2}{5}.\frac{4}{7}.\frac{6}{9}....\frac{44}{47}.\frac{46}{49}\)
a) So sánh A và B
b) Chứng minh A<133
Cho A=\(\frac{1}{4}.\frac{3}{6}.\frac{5}{8}.....\frac{43}{46}.\frac{45}{48}\). CMR A <\(\frac{1}{133}\)
Cho : A = \(\frac{1}{4}\)\(\times\)\(\frac{3}{6}\)\(\times\)\(\frac{5}{8}\)\(\times\).......\(\times\)\(\frac{43}{46}\)
B=\(\frac{3}{5}\)\(\times\)\(\frac{4}{7}\)\(\times\)..........\(\times\)\(\frac{44}{47}\)
a) so sánh A với B
b) chứng minh A<\(\frac{1}{133}\)
1. A = \(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{48}-\frac{1}{49}\)
Chứng minh rằng: \(\frac{1}{5}< A< \frac{2}{5}\)
Chứng minh rằng: Nếu \(\frac{a}{b}=\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{1}{6}+\frac{1}{7}+\frac{1}{8}+\frac{1}{9}+\frac{1}{10}\)
Thì a chia hết cho 13
Tính
a)\(\frac{5}{6}\)+\(6\frac{5}{6}\).(\(11\frac{94}{1591}-6\frac{38}{1517}\)):\(8\frac{11}{43}\)
b) \(1\frac{1}{6}+6\frac{5}{6}.\left(10\frac{133}{2173}-5\frac{23}{1643}\right):41\frac{12}{31}\)
c)\(\frac{0,8:\left(\frac{4}{5}.1,25\right)}{0,64-\frac{1}{25}}+\frac{\left(1,08-\frac{2}{25}\right):\frac{4}{7}}{\left(6\frac{5}{9}-3\frac{1}{4}\right).2\frac{2}{17}}-\left(1,2.0,5\right):\frac{4}{5}\)
Tim x, biet:
\(\frac{x+1}{49}+\frac{x+2}{48}+\frac{x+3}{47}+\frac{x+4}{46}+\frac{x+5}{45}=-5\)
chứng minh rằng \(\frac{1}{2}.\frac{3}{4}.\frac{5}{6}.\frac{7}{8}.......\frac{9999}{1000}< \frac{1}{100}\)