Cho \(B=\dfrac{8}{9}+\dfrac{24}{25}+\dfrac{48}{49}+.........................+\dfrac{200.201}{201^2}\) Chứng minh rằng \(A>99,75\)
Help me!!!!!!!!!!!
b) Cho S = \(\dfrac{1}{2^2}+\dfrac{1}{3^2}+...+\dfrac{1}{9^2}\). Chứng minh rằng \(\dfrac{2}{5}< S< \dfrac{8}{9}\)
Cho A=\(\dfrac{1}{4}\).\(\dfrac{3}{6}\).\(\dfrac{5}{8}\). ... .\(\dfrac{43}{46}\).\(\dfrac{45}{48}\)
B =\(\dfrac{2}{5}\).\(\dfrac{4}{7}\).\(\dfrac{6}{9}\). ... .\(\dfrac{44}{47}\).\(\dfrac{46}{49}\)
a, So sánh A và B
B, Chứng minh A<\(\dfrac{1}{133}\)
help me, chiều mình đi học
a) Tìm số nguyên a sao cho A=\(\dfrac{a^3+3a^2+2a-3}{a+1}\) có giá trị nguyên
b) Cho B=\(\dfrac{1}{2^2}+\dfrac{1}{3^2}+\dfrac{1}{4^2}+......+\dfrac{1}{9^2}\). Chứng minh rằng: \(\dfrac{8}{9}>B>\dfrac{2}{5}\)
Bài 1: Cho b \(\in\) N, b > 1
Chứng minh: \(\dfrac{1}{b}-\dfrac{1}{b+1}< \dfrac{1}{b^2}< \dfrac{1}{b-1}-\dfrac{1}{b}\)
Bài 2: Cho S = \(\dfrac{1}{2^2}+\dfrac{1}{3^2}+\dfrac{1}{4^2}+.....+\dfrac{1}{9^2}\)
Chứng minh: \(\dfrac{2}{5}< S< \dfrac{8}{9}\)
-Giúp tớ với, bí quá :<
Cho \(C=\dfrac{3}{4}+\dfrac{8}{9}+\dfrac{15}{16}+....................+\dfrac{2499}{2500}\) Chứng minh \(C>48\)
Cho \(B=\dfrac{1}{4^2}+\dfrac{1}{6^2}+\dfrac{1}{8^2}+..................+\dfrac{1}{2006^2}\). Chứng minh rằng \(B< \dfrac{334}{2007}\)
Help me!!!!!!!!!!!!!!!
Cho \(S=\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+................+\dfrac{1}{48}+\dfrac{1}{49}+\dfrac{1}{50}\) và \(P=\dfrac{1}{49}+\dfrac{2}{48}+\dfrac{3}{47}+..........+\dfrac{48}{2}+\dfrac{49}{1}\)
Tính \(\dfrac{S}{P}\)
Help me!!!!!!!!!!!
Cho \(A=\dfrac{9}{5^2}+\dfrac{9}{11^2}+..................+\dfrac{9}{305^2}\) Chứng minh rằng \(A< \dfrac{3}{4}\)
