Question

Va rogg, imi trebuie urgent!! ​

Answer 1

Răspuns:

Explicație pas cu pas:

E(x) = (x + 1)^2 + 2(x + 1)(x - 2) + (x - 2)^2

= x^2 + 2x + 1 + 2(x^2 - 2x + x - 2) + x^2 - 4x + 4

= x^2 + 2x + 1 + 2x^2 - 2x - 4 + x^2 - 4x + 4

= 4x^2 - 4x + 1

= (2x - 1)^2

____________

E(√2) = (2√2 - 1)^2 = 8 - 4√2 + 1 = 9 - 4√2

E(√2) + a√2 = 9 - 4√2 + a√2 ∈ N

⇒ a√2 - 4√2 = 0

⇒ a = 4