Răspuns:
Explicație pas cu pas:
calculul din paranteza
x/(x - 1) - x/(x + 1) = [x(x + 1) - x(x - 1)]/(x + 1)(x - 1)
= (x^2 + x - x^2 + x)/(x + 1)(x - 1) = 2x/(x + 1)(x - 1)
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2x/(x + 1)(x - 1) : 2x/(x - 1) = 2x/(x + 1)(x - 1) * (x - 1)/2x = 1/(x + 1)
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x/(x^2 + x) = x/x(x + 1) = 1/(x + 1)
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Expresia devine
E(x) = 1/(x + 1) - 1/(x + 1) = 0
