Ecuatia tangentei intr0un punct
y-yo)=f `(xo)*(x-xo)
yo=f(xo)=f(1)=1-3+1=-3
f `(x)=3x²-3
f `(1)=3-3=0 nu mai are rost sa calculam paranteza
y-(-3)=0*(x-x0)
y+3=0
y=-3
b)y0=f(9)=9+√9=12
f `(x)=1+1/2√x f `(9)=1+1/2*√9=1+1/2*3=7/6
xo=9+√9=9+3=12
Inlocuiesti in ecuatia teangentei
y-12=7/6*(x-12)
y=7x/6-12/6+12
y=7x/6+10
