chứng minh rằng :
\(\frac{1}{4}< \frac{1}{3^2}+\frac{1}{4^2}+\frac{1}{5^2}+...+\frac{1}{50^2}< \frac{4}{9}\)\(\frac{4}{9}\)
\(ChoA=\frac{1}{1^2}+\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{50^2}\)chứng minh rằng A<2
cho A= \(\frac{1}{1^2}+\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{50^2}\) chứng minh rằng A<\(\frac{1}{2}\)
Cho A= \(\frac{1}{1^2}+\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{49^2}+\frac{1}{50^2}\)
CHỨNG MINH RẰNG A<2
Chứng minh rằng:\(\frac{1}{26}+\frac{1}{27}+\frac{1}{28}+....+\frac{1}{49}+\frac{1}{50}=\frac{91}{50}-\frac{97}{49}+\frac{95}{48}-\frac{93}{47}+.....+\frac{7}{4}-\frac{5}{3}+\frac{3}{2}=1\)
cho A=\(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+\frac{1}{5^2}+...+\frac{1}{2011^2}\).chứng minh rằng A<3/4
Cho :
\(A=\frac{1}{1^2}+\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+\frac{1}{5^2}+...+\frac{1}{50^2}\)
Chứng minh A < 2
Cho C = \(\frac{1}{1^2}+\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{50^2}.\).Chứng minh rằng C<2
Cho A= \(\frac{1}{1^2}+\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{49^2}+\frac{1}{50^2}\)
CHỨNG MINH RẰNG A<2