tìm n biết :
\(\frac{1}{8}\)+ \(\frac{1}{24}\)+\(\frac{1}{48}\)+ ...+\(\frac{1}{9800}\)(\(\frac{n+5}{200}\))
Tính:
\(1\frac{1}{3}.1\frac{1}{8}.1\frac{1}{15}.1\frac{1}{24}.....1\frac{1}{9800}\)
\(1\frac{1}{3}.1\frac{1}{8}.1\frac{1}{15}....1\frac{1}{9800}=\frac{4}{3}.\frac{9}{8}.\frac{16}{15}....\frac{9801}{9800}\)
\(=\frac{2.2}{1.3}.\frac{3.3}{2.4}.\frac{4.4}{3.5}....\frac{99.99}{98.100}\)
\(=\frac{2.3.4...99}{1.2.3....98}.\frac{2.3.4...99}{3.4.5...100}\)
\(=99.\frac{2}{100}=99.\frac{1}{50}=\frac{99}{50}\)
Bài 5:Tính
A=\(1\frac{1}{3}.1\frac{1}{8}.1\frac{1}{15}.1\frac{1}{24}.1\frac{1}{35}\cdot...\cdot1\frac{1}{9800}\)
Mấy số trên là hỗn số đó
\(A=\frac{4}{3}.\frac{9}{8}.\frac{16}{15}.\frac{25}{24}.\frac{36}{35}......\frac{9801}{9800}=\frac{\left(2.3.4.5....99\right)^2}{1.3.2.4.3.5.4.6.....98.100}=\frac{2.3.4.5...99}{1.2.3.4.....98}.\frac{2.3.4.5....99}{3.4.5.6......100}=\frac{99}{1}.\frac{2}{100}=\frac{99}{50}\)
A=4/3.9/8.16/15.25/24. ... .9801/9800
Tính được chưa
Tính :
a) \(S=\frac{1}{5}+\frac{1}{20}+\frac{1}{44}+...+\frac{1}{1175}\)
b)\(S=1\frac{1}{3}.1\frac{1}{8}.1\frac{1}{15}.1\frac{1}{24}.1\frac{1}{35}.....1\frac{1}{9800}\)
tính nhanh: \(1\frac{1}{4}\times1\frac{1}{8}\times1\frac{1}{15}\times1\frac{1}{24}\times1\frac{1}{35}\times...\times1\frac{1}{9800}\)
tìm N:M biết
\(M=\frac{1}{2}-\frac{3}{4}+\frac{5}{6}-\frac{7}{8}+...+\frac{197}{198}-\frac{199}{200}\)
\(N=\frac{1}{51}+\frac{1}{52}+...+\frac{1}{100}\)
help me
Tìm x biết: \(1.\frac{1}{30}:\left(24.\frac{1}{6}-24.\frac{1}{5}\right)-\frac{1.\frac{1}{2}-\frac{3}{4}}{4.x-\frac{1}{2}}=\left(-1.\frac{1}{15}\right):\left(8.\frac{1}{5}-8.\frac{1}{3}\right)\)
Tìm x biết \(1\frac{1}{30}:\left(24\frac{1}{6}-24\frac{1}{5}\right)-\frac{1\frac{1}{2}-\frac{3}{4}}{4x-\frac{1}{2}}=\left(-1\frac{1}{15}\right):\left(8\frac{1}{5}-8\frac{1}{3}\right)\)
tìm x biết : \(1\frac{1}{3}:\left(24\frac{1}{6}-24\frac{1}{5}\right)-\frac{1\frac{1}{2}-\frac{3}{4}}{4x-\frac{1}{2}}=\left(-1\frac{1}{15}\right):\left(8\frac{1}{5}-8\frac{1}{3}\right)\)
Tìm x biết \(1\frac{1}{30}:\left(24\frac{1}{6}-24\frac{1}{5}\right)-\left(1\frac{1}{2}-\frac{3}{4}\right):\left(4x-\frac{1}{2}\right)=\left(-1\frac{1}{15}\right):\left(8\frac{1}{5}-8\frac{1}{3}\right)\)