Sửa đề:
\(Q=\frac{\frac{1}{2}+\frac{1}{3}+...+\frac{1}{100}}{\frac{100-1}{1}+\frac{100-2}{2}+...+\frac{100-99}{99}}\)
\(=\frac{\frac{1}{2}+\frac{1}{3}+...+\frac{1}{100}}{100-1+\frac{100}{2}-1+...+\frac{100}{99}-1}\)
\(=\frac{\frac{1}{2}+\frac{1}{3}+...+\frac{1}{100}}{\frac{100}{100}+\frac{100}{2}+\frac{100}{3}+...+\frac{100}{99}}\)
\(=\frac{\frac{1}{2}+\frac{1}{3}+...+\frac{1}{100}}{100.\left(\frac{1}{2}+\frac{1}{3}+...+\frac{1}{99}+\frac{1}{100}\right)}=\frac{1}{100}\)
Xét K=\(\frac{100-1}{1}+\frac{100-2}{2}+...+\frac{100-99}{99}\)
=\(\frac{100}{1}-1+\frac{100}{2}-1+...+\frac{100}{99}-1\)
= \(100.\left(\frac{1}{1}+\frac{1}{2}+...+\frac{1}{99}\right)-\left(1+1+...+1\right)\)
= \(100+100.\left(\frac{1}{2}+\frac{1}{3}+...+\frac{1}{99}\right)-99\)
=\(1+100.\left(\frac{1}{2}+...+\frac{1}{99}\right)=100.\left(\frac{1}{2}+...+\frac{1}{99}+\frac{1}{100}\right)\)
=> Q=1/100