Question

Ex 4 + coroana si 10 p

Answer 1

Rezolvarea mai jos!!!!!

Answer 2

$a = (-1)^n\cdot (-2)+(-1)^{n+2}\cdot 3-(-1)^{2n+3}\cdot (-4)$

Daca n este par, atunci:

$a = (-1)^n\cdot (-2)+(-1)^{n+2}\cdot 3-(-1)^{2n+3}\cdot (-4)=$
$=-2+3-(-1)\cdot (-4)=-2+3-4=\\=-3$

Daca n este impar, atunci:

$a = (-1)^n\cdot (-2)+(-1)^{n+2}\cdot 3-(-1)^{2n+3}\cdot (-4)=$
$=-1\cdot (-2)+(-1)\cdot 3-(-1)\cdot (-4)=\\=2-3-4=\\=-5$