Question

Aflati valoare expresiei:.........................Imi trebuie foarte urgent .......Care imi rs primul primeste totodata shi coroana.

Answer 1

[tex]Vom\ avea\ de\ analizat\ doua\ cazuri:\\ i)n=2k,k\in Z(altfel\ spus\ cand\ n\ este\ par):\\ E=\frac{1}{2}\cdot (-1)^{2k}+\frac{1}{4}\cdot (-1)^{2k+1}+\frac{3}{4}\cdot (-1)^{2k+2}\\ \\ E=\frac{1}{2}-\frac{1}{4}+\frac{3}{4}\\ \\ E=\frac{1}{2}+\frac{1}{2}=\boxed{1}\\ \\ ii)n=2k+1,k\in Z(cand\ n\ este\ impar)\\ E=\frac{1}{2}\cdot(-1)^{2k+1}+\frac{1}{4}\cdot(-1)^{2k+2}+\frac{3}{4}\cdot(-1)^{2k+3}\\ \\ E=-\frac{1}{2}+\frac{1}{4}-\frac{3}{4}=\boxed{-1}\\ [/tex]