(1^n+2^n+3^n+4^n)^1/n=e^{ln[(1^n+2^n+3^n+4^n)^1/n]}=e^{(1/n)*ln(1^n+2^n+3^n+4^n)}lim(n->∞) (1/n)*ln(1^n+2^n+3^n+4^n) (用咯比达法则)=lim(n->∞) [(ln1*1^n+ln2*2^n+ln3*3^n+ln4*4^n)/(1^n+2^n+3^n+4^n)]=...