Tính A:

A= 1/3 + 1/9 + 1/27 + ...........+ 1/243 + 1/729

Tính A:

A=2/6 . 12/20 . 30/42 . 56/72 . ...... . 9900/101

Tính C:

C= 4/1.3 + 9/2.4 + 16/3.5 + ..... + 2401/48.50

Tính:

A=1/2.9 + 1/9.7 + 1/7.19 + ... + 1/252.509

B=5/1.4 + 29/4.7 + 71/7.10 + 10301/100.103

\(\frac{1.4}{4.6}+\frac{2.5}{6.8}+\frac{3.6}{8.10}+.........+\frac{48.51}{98.100}\)

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