3) f'(x) = 3x²+6x+3 f'(x)=0
3x²+6x+3=0
D=36-36=0
x=-6/6=-1
f'(x)=x²+2x+3
x²+2x+3=0
D=4-12=-8 <0 <br>∅
4)f'(x)= 2/3x
f'(0)=0
f(0)1/3 * 0+1=1
y=f'(x0)*(x-x0)+f(x0)
y=0*(x-0)+1=1
5)f'(x)=4(-8x²+1)³ * (-16x)=-64x(-8x²+1)³
f'(x)=-sin2x*2+cos2x*2= 2cos2x-2sin2x