Tính \(1+\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+\frac{1}{15}+......+\frac{1}{120}\)
Tính tổng:
a) \(A=\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+...+\frac{1}{120}\)
b) \(B=1+\frac{1}{3}+\frac{1}{6}+...+\frac{1}{1225}\)
Giúp mik nha, mik đang cần gấp
Câu 1
Tính giá tri biểu thức
A=\(\frac{\frac{7}{12}+\frac{5}{6}-1}{5-\frac{3}{4}+\frac{1}{3}}\)
B= \(1+3^1+3^2+3^3+...+3^{99}\)
C= \(1+\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{2}{x\left(x+1\right)}\)(với x\(\in\)N)
D= \(\frac{9}{8}.\frac{16}{15}.\frac{25}{24}.....\frac{8100}{8099}\)
Thực hiện phép tính:
\(\left(1-\frac{1}{3}\right)\left(1-\frac{1}{6}\right)\left(1-\frac{1}{10}\right)\left(1-\frac{1}{15}\right)...\left(1-\frac{1}{780}\right)\)
Giúp mình nhé, xong trước ngày 13/2
\(\text{Tính tổng }A=\frac{1}{2}+\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+\frac{1}{15}+...+\frac{1}{36}+\frac{1}{45}\)
Tinh A biet : A=\(\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+...+\frac{1}{120}.\)
Tính:
a) \(A=\frac{\frac{\frac{1}{2}+\frac{1}{3}+\frac{1}{7}}{\frac{8}{2}+\frac{8}{3}+\frac{8}{7}}}{\frac{\frac{1}{7}+\frac{1}{8}+\frac{1}{92}}{\frac{4}{7}+\frac{4}{8}+\frac{4}{92}}}\) ;b) \(B=\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+.........+\frac{1}{120}\)
Giúp mình vs mình tick cho.
tìm x
\(a,\frac{x}{2008}-\frac{1}{10}-\frac{1}{15}-\frac{1}{21}-...-\frac{1}{120}=\frac{5}{8}\)