\(\frac{(1+2+3+..+100).)(\frac{1}{3}+\frac{1}{5}+\frac{1}{7}+\frac{1}{9}).(6,3.12-3,6.21)}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)
=\(\frac{(1+2+3+..+100).)(\frac{1}{3}+\frac{1}{5}+\frac{1}{7}+\frac{1}{9}).0}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)
=\(\frac{0}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\) =0
Chúc anh hk tốt.