b) f `(x)=(x) `-3(lnx) `=1-3/x
c)Ecuatia tangentei in puncyul (xo,yo)
y-f(xo)=f `(xo)*(x-x0)
y-f(1)=f `(1)*(x-1) f(1)=1 f `(1)= - 2
y-1=-2*(x-1)
y=-2x+3
x→2 lim (f(x)-2)/(x-2)= lim[(x-3lnx)-2+3ln3]/x-2)=lim[(x-2)/(x-2)-(3lnx+3ln2)/(x-2)=1-3lim ln2/x /(x-2)
f