[tex]x^2+mx+1=0\\
\triangle=b^2-4ac=m^2-4\\
m^2-4=0=>m^2=4=>m_{1/2}=\pm 2[/tex]
m -infinit -2 +2 +infinit
m^2-4 ++++++++++++++++++0-------------------------------0++++++++++++++++++++++
Concluzie:
1)Daca m=-2 sau m=2=> delta=0=> ecuatia are radacini reale egale
2)Daca m∈(-∞;-2)U(2;+∞)=>delta>0=> ecuatia are radacini reale diferite
3)Daca m∈(-2;2)=>delta<0=> ecuatia nu are radacini reale.
