Question

calcule os arranjos simples de
a) A 7,4=
b)A 5,2=
c) A 4,2 + A 7,3=​

Answer 1

a) A7,4 = 840

$\large{ \sf{A7,4 = \dfrac{7!}{(7 - 4)!}}}$

$\large{ \sf{A7,4 = \dfrac{7!}{3!}}}$

$\large{ \sf{A7,4 = \dfrac{ 7 \cdot 6 \cdot 5 \cdot4 \cdot3!}{3!}}}$

$\large{ \sf{A7,4 = 840}}$

b) A5,2 = 20

$\large{ \sf{A5,2 = \dfrac{5!}{(5 - 2)!}}}$

$\large{ \sf{A5,2 = \dfrac{5!}{3!}}}$

$\large{ \sf{A5,2 = \dfrac{5 \cdot4 \cdot3!}{3!}}}$

$\large{ \sf{A5,2 = 20}}$

c) A4,2 + A7,3 = 852

$\large{ \sf \dfrac{4!}{(4 - 2)!} + \dfrac{7!}{(7 - 3)!}}$

$\large{ \sf{ \dfrac{4!}{2!} + \dfrac{7!}{4!}}}$

$\large{ \sf{ \dfrac{4 \cdot3 \cdot2!}{2!} + \dfrac{7 \cdot6 \cdot5 \cdot4!}{4!}}}$

$\large{ \sf{12 + 840 = 852}}$