Giúp mình vài bài này với: Cho a,b,c>0, CMR:
1/ $$\frac{a^{8}+b^{8}+c^{8}}{a^{3}b^{3}c^{3}}\geqslant \frac{1}{a}+\frac{1}{b}+\frac{1}{c}$$
2/ $$\frac{a^{2}+b^{2}}{c}+\frac{b^{2}+c^{2}}{a}+\frac{c^{2}+a^{2}}{b}\geq 2(a+b+c)$$
3/ $$\frac{2\sqrt{a}}{a^{3}+b^{2}}+\frac{2\sqrt{b}}{b^{3}+c^{2}}+\frac{2\sqrt{c}}{c^{3}+a^{2}} \leq \frac{1}{a^{2}}+\frac{1}{b^{2}}+\frac{1}{c^{2}}$$