Question

c, C = 2/1.3 + 2/3.5 + 2/5.7 + .......+ 2/69.71+ 2/71.73

Answer 1

ta có:

C = 1 - 1/3 + 1/3 - 1/5 +...+1/69 - 1/71 + 1/71 - 1/73

    = 1 - 1/ 73

    = 72/73

Answer 2

\(C=\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{69.71}+\)\(\frac{2}{71.73}\)

\(C=1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{69}-\frac{1}{71}+\frac{1}{71}-\frac{1}{73}\)

\(C=1-\frac{1}{73}\)

\(C=\frac{72}{73}\)

Answer 3

c) C = 1 - 1/3 + 1/3 - 1/5 + ... + 1/71 - 1/73

        = 1 - 1/73

        = 72/73

ủng hộ mk nha!