1 Tính:
B=\(\frac{2}{5\text{x}8}+\frac{2}{8\text{x}11}+\frac{2}{11\text{x}14}+..........+\frac{2}{95\text{x}98}\)
Tính: \(\frac{\frac{99}{1}+\frac{98}{2}+\frac{97}{3}+...+\frac{2}{98}+\frac{1}{99}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{99}+\frac{1}{100}}\)
\(A=\left(1+\frac{1}{2}\right)x\left(1+\frac{1}{3}\right)x\left(1+\frac{1}{4}\right)x...x\left(1+\frac{1}{98}\right)x\left(1+\frac{1}{99}\right)\)
\(A=\)
TÍNH :
\(\left(1+\frac{1}{2}\right)\)\(x\left(1+\frac{1}{3}\right)\)\(x\left(1+\frac{1}{4}\right)\)\(x......x\left(1+\frac{1}{98}\right)x\left(1+\frac{1}{99}\right)\)
\(\frac{1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{99}+\frac{1}{100}}{\frac{1}{99}+\frac{2}{98}+\frac{3}{97}+...+\frac{99}{1}+100}=?\)
2 x \(\frac{1+3+5+...+99}{2+4+6+...+98+x}=1\)
\(\frac{1}{2}+\frac{2}{3}+\frac{3}{4}+...+\frac{99}{100}\)
\(\frac{1}{99}+\frac{2}{98}+\frac{3}{97}+...+\frac{99}{1}\)
\(\frac{1}{2}+\frac{2}{3}+\frac{3}{4}+........+\frac{98}{99}+\frac{99}{100}\)
Tính nhanh :
\(\frac{18\cdot25+9\cdot45\cdot2+3\cdot27\cdot6}{100-99+98-97+96-95+...+2-1}\)