a) lim f(x)=0/0 x→0 Aplici teorema L`Hospital
l=lim(x-arctg x) `/(x³) `=(1-1/(x²+1))/3x²=x²/3x²=1/3
b)x→o l=limln0/lno=-∞/-∞. Aplici L` Lospital
l=lim (ln sin 2x) `/ln(sinx) ` =lim (sin2x) `/ (sin2x) `:(cos x/sinx)=lim (2 cos 2x)/2sinx *2simx*cos x)*sinx/cosx=lim(2cos² -1)x/cos x*cos x=2-1=1 x→0