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calculati : S2 va rog

Calculati S2 Va Rog class=

Răspuns :


Folosim relația:

[tex]\it \dfrac{2}{k(k+2)} = \dfrac{1}{k} - \dfrac{1}{k+2}[/tex]

[tex]\it S_2 = \dfrac{1}{1} -\dfrac{1}{3} +\dfrac{1}{3} -\dfrac{1}{5}+\dfrac{1}{5} -\dfrac{1}{7}+ ... +\dfrac{1}{13} -\dfrac{1}{15} = 1 -\dfrac{1}{15}[/tex]