Tìm x, biết: \(\frac{\left(1\times2+2\times3+3\times4+..........+98\times99\right)\times x}{26950}=\frac{51}{4}\div\frac{3}{2}\)
\(\frac{1\times2}{2\times3}+\frac{2\times3}{3\times4}+\frac{3\times4}{4\times5}+...+\frac{98\times99}{99\times100}\)
Tính biểu thức A
\(A=\frac{5}{1\times2}+\frac{5}{2\times3}+\frac{5}{3\times4}+...+\frac{5}{98\times99}+\frac{5}{99\times100}\)
\(y=\frac{1\times100+2\times99+3\times98...+99\times2+100\times1}{1\times2+2\times3+3\times4+...+99\times100+100\times101}=?\)
Tìm số nguyên tố \(n\) lớn nhất để: \(\left(1\times2\times3\times...\times97\times98\right)+\left(1\times2\times3\times...\times98\times99\times100\right)⋮n\)
CHO A = \(\frac{2\times9\times8+3\times12\times10+4\times15\times12+...+98\times297\times200}{2\times3\times4+3\times4\times5+4\times5\times6+...+98\times99\times100}\)
TÍNH A\(^2\)
Tính :
A = \(\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+\frac{1}{2^4}+...+\frac{1}{2^{99}}+\frac{1}{2^{100}}\)
B = \(\frac{1}{1\times2}+\frac{1}{2\times3}+\frac{1}{3\times4}+...+\frac{1}{98\times99}+\frac{1}{99\times100}\)
Tìm x:
\(\frac{1}{1\times2}+\frac{1}{2\times3}+\frac{1}{3\times4}+...+\frac{1}{x\times\left(x+1\right)}=\frac{2015}{2016}\)
Tính:
\(A=\frac{1^2}{1\times2}\times\frac{2^2}{2\times3}\times\frac{3^2}{3\times4}\times...\times\frac{99^2}{99\times100}\times\frac{100^2}{100\times101}\)