Question

Calculati E=3•(-1)^n+2 + 4•(-1)^2n+1

Answer 1

$E = 3\cdot(-1)^{n+2}+4\cdot(-1)^{2n+1} = \\ =3\cdot (-1)^n \cdot (-1)^2+4\cdot (-1)^{2n}\cdot (-1)^1 = 3\cdot \pm 1\cdot 1+ 4\cdot 1\cdot (-1) = \\ =\pm 3-4 \\ \\ Daca n este par: \Rightarrow E = 3-4 \Rightarrow \boxed{E = -1} \\ Daca n este impar: \Rightarrow E = -3-4 \Rightarrow \boxed{E = -7}$