logb[a^logc(b)] =logc(b)*logb(a) =(lgb/lgc)*(lga/lgb) =lga/lgc =logc(a) logb[b^logc(a)]=logc(a) 所以logb[a^logc(b)]=logb[b^logc(a)] 所以a^logc(b)=b^logc(a)
