Neocijenjeno
Oct. 3, 2023, 10:47 a.m. (2 years, 11 months)
Neka je
. Izračunaj sljedeću sumu:
Neka je $n \in \mathbb{N}$. Izračunaj sljedeću sumu:
$$1\cdot 1!+2\cdot 2!+\ldots +n\cdot n!$$
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$2!-1!=1\cdot1!$
$3!-2!=2\cdot2!$
$4!-3!=3\cdot3!$
$\vdots$
$(n+1)!-n!=n\cdot n!$
Zbrajanjem dobivamo:
$(n+1)!-1=1\cdot1!+ 2\cdot2! +...+n\cdot n!$