Cho B= \(\dfrac{8}{9}+\dfrac{24}{25}+\dfrac{48}{49}+...+\dfrac{200.202}{201^2}\). Chứng minh rằng B>99,75
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
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 \(B=\dfrac{1}{4^2}+\dfrac{1}{6^2}+\dfrac{1}{8^2}+..................+\dfrac{1}{2006^2}\). Chứng minh rằng \(B< \dfrac{334}{2007}\)
Help me!!!!!!!!!!!!!!!
Cho \(A=\dfrac{1}{2^2}+\dfrac{1}{3^2}+\dfrac{1}{4^2}+................+\dfrac{1}{9^2}\)
Chứng minh \(\dfrac{2}{5}< A< \dfrac{8}{9}\)
Help me!!!!!!!!!!! tôi đang cần gấp!!!
Cho \(A=\dfrac{11}{9}+\dfrac{18}{16}+................+\dfrac{1766}{1764}\)Chứng minh rằng \(40\dfrac{23}{43}< A< 40\dfrac{20}{21}\)
Help me!!!!!!!!!!!
b) Cho S = \(\dfrac{1}{2^2}+\dfrac{1}{3^2}+...+\dfrac{1}{9^2}\). Chứng minh rằng \(\dfrac{2}{5}< S< \dfrac{8}{9}\)
1)
Cho \(\dfrac{1}{20}+\dfrac{1}{21}+\dfrac{1}{22}+...+\dfrac{1}{200}\)
Chứng minh: \(A>\dfrac{9}{10}\)
2)
Cho \(B=\dfrac{1}{101}+\dfrac{1}{102}+\dfrac{1}{103}+...+\dfrac{1}{200}\)
Chứng minh: \(B>\dfrac{7}{12}\)
HELP ME!!!!!!!!
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: \(\dfrac{8}{9}>B>\dfrac{2}{5}\)