Bài 1: Cho $a,b,c \in \mathbb{R}$ thỏa mãn $(a-b)(b-c)(c-a)\neq 0$ . CMR:
$\frac{a^2(a+b)(a+c)}{(a-b)(a-c)}+\frac{b^2(b+c)(b+a)}{(b-c)(b-a)} +\frac{c^2(c+a)(c+b)}{(c-a)(c-b)}\ge 0$
Bài 2: Cho $a,b,c \mathbb{R}$ thỏa mãn $ a>b>c$ CMR
$\frac{a^2}{a-b}+\frac{b^2}{b-c}> a+c+2b$