1. 证明 3(a^5+b^5+c^5) >= (a^3+b^3+c^3)(a^2+b^2+c^2)3(a^5+b^5+c^5) - (a^3+b^3+c^3)(a^2+b^2+c^2)=3(a^5+b^5+c^5) - { a^5+b^5+c^5 + a^3b^2 + a^2b^3 + b^3c^2 + b^2c^3 + c^3a^2 + c^2a^3 }=(a^5-a^3b^2-a^2b^...