Question

Ajutor!!






$E(X)=(2-\frac{8}{X+2} ):\frac{x^{2} -4X+4}{x^{2} -4}$
Aratati ca E(X)=2 p/u orice X numar real,X diferit de 2 si -2

Answer 1

Răspuns:

E(x)=(2-8/(x+2)):(x²-4x+4)/(x²-4)=

[(2(x+2)-8)/(x+2)]:(x-2)²/(x-2)(x+2)=

[(2x+4-8)/(x+2)]:(x-2)/(x+2)=

(2x-4)/(x+2)·(x+2)/(x-2)=

2(x-2)·1/(x-2)=2

Explicație pas cu pas: