Question

Calcule A4,2 - A2,1
Com as resoluções

Answer 1

$Arranjo \: simples \\ \\ A^{p} _n = \frac{n!}{(n - p)!} \\ \\ A^{2} _4 - A^{1} _2 \\ \frac{4!}{(4 - 2)!} - \frac{2!}{(2 - 1)!} \\ \\ \frac{4!}{2!} - \frac{2!}{1!} = 12 - 2 = 10$