у=3х^4+4x^3+1,
y'=12x^3+12x^2,
y'=0, 12x^3+12x^2=0,
12x^2(x+1)=0,
x^2=0, x_1=0,
x+1=0, x_2=-1,
f(-2)=17,
f(-1)=0,
f(0)=1,
f(1)=8,
min_{x∈[-2;1]}=0, x=-1,
max_{x∈[-2;1]}=17, x=-2.
