tính \(\frac{A}{B}\)
a. A= \(\frac{4}{7.31}+\frac{6}{7.41}+\frac{9}{10.41}+\frac{7}{10.57}\) B = \(\frac{7}{19.31}+\frac{5}{19.43}+\frac{3}{23.43}+\frac{11}{23.57}\)
b. A= \(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2017}\) B = \(\frac{2016}{1}+\frac{2015}{1}+\frac{2014}{1}+...+\frac{1}{2016}\)