x→-∞ limf(x)=lim(3x+e^x)=3*(-∞)+e^(-∞)=-∞
Functia nu are asimptote la -∞
b)3x+e^x≥4x+1
3x+e^x-4x-1≥0
Fie g(x)=3x+e^x-4x-1
Calculezi punctele de extrem
g `(x)=3+e^x-4=e^x-1
e^x-1=0 e^x=1 x=0
Pt x<0 g `(x)<0 =>g(x) descrescatoare
Pt x>0 g `(x)=e(x-1>0 g(x) crescatoare=> x=0 punct de minim
Functia g ia valoarea minima in x=0 g(0)=0=>
∀x≠0 g(x)>0 adica
3+e^x-4x-1>0
adica
3+e^x≥4x+1