c明显小于0，a>b>0.对a，b同时取对数loga=(1/3)*log(1/2);logb=(1/2)*log(1/3);loga=-(1/3)*log(2)<0;logb=-(1/2)*log(3)<0;(loga)/(logb)=(2*log(2))/(3*log(3))<1;又loga,logb<0;所以a>b
