Răspuns:
Explicație pas cu pas:
Prima paranteza:
1 - (x + 1)/(x - 1) + (4x + 4)/(x^2 - 1) =
= 1 - (x + 1)/(x - 1) + 4(x + 1)/(x + 1)(x - 1) =
= 1 - (x + 1)/(x - 1) + 4/(x - 1) =
= (x - 1)/(x - 1) - (x + 1)/(x - 1) + 4/(x - 1) = (x - 1 - x - 1 + 4)/(x - 1) = 2/(x - 1)
_________
E(x) = 2/(x - 1) * (x + 1) - 4/(x - 1) = [2(x + 1) - 4] / (x - 1) = (2x + 2 - 4)/(x - 1) =
= (2x - 2) / (x - 1) = 2(x - 1)/(x - 1) = 2