\(\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right)..................\left(1-\frac{1}{20}\right)\)
=\(\frac{1}{2}.\frac{2}{3}.............\frac{19}{20}\)
=\(\frac{1.2.3..............19}{2.3.4..............20}\)
=\(\frac{1}{20}\)
Tính : \(B=1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+...+\frac{1}{20}\left(1+2+...+20\right)\)
Tính:
\(A=1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+......+\frac{1}{20}\left(1+2+3+....+20\right)\)
Help tìm x: \(\left|x+\frac{1}{2}\right|+\left|x+\frac{1}{6}\right|+\left|x+\frac{1}{12}\right|+\left|x+\frac{1}{20}\right|+...+\left|x+\frac{1}{110}\right|=11x\)
Tính \(\frac{1}{2}+\left(\frac{1}{2}\right)^2+\left(\frac{1}{2}\right)^3+...+\left(\frac{1}{2}\right)^{98}+\left(\frac{1}{2}\right)^{99}+\left(\frac{1}{2}\right)^{99}\)
Tính:
A=\(\left(\frac{1}{2}-1\right).\left(\frac{1}{3}+1\right).\left(\frac{1}{4}+1\right)....\left(\frac{1}{99}+1\right)\)
help me: \(\left(6.\left(-\frac{1}{3}\right)^2-3.\left(-\frac{1}{3}\right)+1\right):\left(-\frac{1}{3}-1\right)\)
rút gọn biểu thức sau
\(log_2\left(2a^2\right)+\left(log_2^a\right)a^{log_a\left(log_2^a+1\right)}+\frac{1}{2}log^2_2a^4\)
Tính B=$\frac{1}{3} \frac{1}{6}\left(1 2\right) \frac{1}{9}\left(1 2 3\right) ... \frac{1}{6045}\left(1 2 3 ... 2015\right)$13 16 (1 2) 19 (1 2 3) ... 16045 (1 2 3 ... 2015)
