Question

2!/0!+3!/1!+...+10!/8!​

Answer 1

Explicație pas cu pas:

$\frac{2l}{0l} + \frac{3l}{1l} + ... + \frac{10l}{8l} = \\ \frac{1 \times 2}{0} + \frac{1l \times 2 \times 3}{1l} + \frac{2l \times 3 \times 4}{2l} + ... + \frac{8l \times 9 \times 10}{8l} = \\ 0 + 2 \times 3 +3 \times 4 + 4 \times 5 + 5 \times 6 + 6 \times 7 + 7 \times 8 + 8 \times 9 + 9 \times 10 = \\ 0 + 6 + 12 +20 + 30 + 42 + 56 + 72 + 90 = 328$