Răspuns:
f(x)=(x-1)(x-2)(x-3)+4=
(x²-3x+2)(x-3)+4
f `(x)=(x²-3x+2) `(x-3)+(x²-3x+2)(x-3) `+4 `=
(2x-3)(x-3)+(x²-3x+2)*1+0=
2x²-3x-6x+9+x²-3x+2=
3x²-12x+11
f `(x)=0
3x²-12x+11=0
Ecuatie de gradul 2.Daca disriminantul Δ>0, ecuatia admite 2 radacini reale
Δ=(-12)²-4*3*11=
144-132=12>0
Ecuatia f `(x)=0 are 2 radacini reale ∀x∈R
Explicație pas cu pas: