Salut! Va rog sa ma ajutati :(
Calculati:
[tex] (\frac{1}{1 \times 2} + \frac{1}{2 \times 3} + \frac{1}{3 \times 4} + .... + \frac{1}{29 \times 30} ) -( \frac{1}{1 \times 2} + \frac{1}{2 \times 3} + \frac{1}{3 \times 4} + .... + 1 \\ \frac{1}{14 \times 15}) \\ ( \frac{3}{1 \times 4} + \frac{3}{4 \times 7} + \frac{3}{7 \times 10} + ... + \frac{3}{25 \times 28}) - ( \frac{4}{1 \times 5} + \frac{4}{5 \times 9} + \frac{4}{9 \times 13} + ... + \frac{4}{25 \times 29} )[/tex]
Multumesc! Apropo dau coroana ​VA ROOOG AJUTOR