1) f(x) = 1/3x^3-2x^2+3x+4
f(1/3x^3-2x^2+3x+4)` = 1/3*3x^2-4x+3 = x^2-4x+3
2) y`= 0, x^2-4x+3
x^2-4x+3=0
x =( -(-4)+- корень из (-4)^2-4*1*3) / (2*1)
x = (4+- корень из 16-12) / 2
x = (4+- корень из 4) / 2
x = (4+-2) / 2
x1 = 1, x2 = 3
3) f(x^2-4x+3)`` = 2x-4
y``(0) = 2*0-4 = -4 < 0
x=0 - max
y``(2) = 2*2-4 = 0
y``(4) = 2*4-4 = 4 > 0
x = 4 - min
4) 1/3x^3-2x^2+3x+4
y(1) = 1/3*1^3-2*1^2+3*1+4 = 5,3 - max (1; 5,3)
y(3) = 1/3*3^3-2*3^2+3*3+4 = 4 - min (3; 4)
Ответ: max (1; 5,3), min (3; 4)