Răspunsuri

2014-01-19T17:58:59+02:00
 \frac{1}{ \sqrt{x-1} \sqrt{x+1} }
= \frac{1}{ x^{2} +1}
 x^{2} +1≤0
1/√x-1/√x+1>0 rationalizez si obtin √x/x-√x/x+1>O aduc la acelasi numitor si imi da x>o