\(\dfrac{1}{3}-\dfrac{1}{101}=\dfrac{101}{303}-\dfrac{3}{303}=\dfrac{98}{303}\)
\(\dfrac{1}{3}-\dfrac{1}{101}=\dfrac{101}{303}-\dfrac{3}{303}=\dfrac{98}{303}\)
So sánh:
a)\(\dfrac{1}{101}+\dfrac{1}{102}+\dfrac{1}{103}+...+\dfrac{1}{200}\) với 1
b)\(\dfrac{1}{101}+\dfrac{1}{102}+...+\dfrac{1}{149}+\dfrac{1}{150}\) với\(\dfrac{1}{3}\)
c)\(\dfrac{1}{101}+\dfrac{1}{102}+\dfrac{1}{103}+...+\dfrac{1}{200}\) với \(\dfrac{7}{12}\)
2. Chứng minh
a, \(\dfrac{1}{2^2}\)+\(\dfrac{1}{3^2}\)+\(\dfrac{1}{4^2}\)+...+\(\dfrac{1}{50^2}\) < 1
b, \(\dfrac{1}{3}\)< \(\dfrac{1}{101}\)+\(\dfrac{1}{102}\)+\(\dfrac{1}{103}\)+...+\(\dfrac{1}{150}\)< \(\dfrac{1}{2}\)
cho A = \(\dfrac{1}{101}+\dfrac{1}{102}+\dfrac{1}{103}+...+\dfrac{1}{300}\), e hãy chứng minh A>\(\dfrac{2}{3}\)
\(\dfrac{1}{5}+\dfrac{1}{5^2}+\dfrac{1}{5^3}+...+\dfrac{1}{5^{100}}+\dfrac{1}{5^{101}}\)
GIÚP MIK TỪNG BƯỚC 1 NHÉ
tìm x
\(\dfrac{1}{5\cdot8}\)+\(\dfrac{1}{8\cdot11}\)+\(\dfrac{1}{11\cdot13}\)+...+\(\dfrac{1}{x\left(x+3\right)}\)=\(\dfrac{101}{1540}\)
so sánh: M= \(\dfrac{101^{102}+1}{101^{103}+1}\) và N= \(\dfrac{101^{103+1}}{101^{104}+1}\)
Chứng minh rằng số tự nhiên A chia hết cho 101 với:
A=1.2.3...99.100,(1\(\dfrac{1}{2}+\dfrac{1}{3}+...+\dfrac{1}{99}+\dfrac{1}{100}\))
. Cho \(M=\dfrac{101^{102}+1}{101^{103}+1}\) và N = \(\dfrac{101^{103}+1}{101^{104}+1}\) So sánh M và N.
cmr \(\dfrac{1}{101}+\dfrac{1}{102}+\dfrac{1}{103}+...+\dfrac{1}{199}+\dfrac{1}{200}>\dfrac{1}{2}\)
\(A =\)\(\dfrac{101+100+99+98+...+3+2+1}{101-100+99-98+...+3-2+1}\)
\(B=\) \(\dfrac{3737.43-4343.37}{2+4+6+...+100}\)
Làm cách lớp 6 thôi ah