Doar a doua suma e valida.
Celelalte sunt scrise greșit.
[tex] \dfrac{3}{9}+\dfrac{4}{12}+...+\dfrac{1004}{3012} = \\ \\ = \sum\limits_{k=3}^{1004} \dfrac{k}{3k} = \sum\limits_{k=3}^{1004} \dfrac{1}{3} = \\ = \sum\limits_{k=1}^{1002} \dfrac{1}{3} = \dfrac{1}{3}\cdot 1002 = \\ \\ = \dfrac{1002}{3}=334 [/tex]
