f'=1+2/3*x^(-1/3)3x^1/3=-2x=(-2/3)^3x=-8/27f(-1)=-1+(-1)^2/3=0- минимумf(3)=3+9^1/3 максимумf(-8/27)=-8/27+4/9=12/27-8/27=4/27.
f'=1+2/3*x^(-1/3)
3x^1/3=-2
x=(-2/3)^3
x=-8/27
f(-1)=-1+(-1)^2/3=0- минимум
f(3)=3+9^1/3 максимум
f(-8/27)=-8/27+4/9=12/27-8/27=4/27.