[tex]f'_{x_A}=f'_{x_B}<=>3x_{A}^2-6x_{A}=3x_{B}^2-6x_{B}=> x_{a}+x_{B}-2=0<=>x_{A}=2-x_{B}[/tex]
[tex]A(a;a^3-3a^2+1);B(b;b^3-3b^2+1)[/tex]
[tex]AB^2=(a-b)^2+(a^3-3a^2-b^3+3b^2)^2=32<=>(2-2b)^2+[(2-b)^3-3(2-b)^2-b^3+3b^2]^2=32=> b=-1 ; b=3[/tex]
thay zô ra tọa độ A, B