令a=1/x则a→∞(1+x)/(1-x)=(1+1/a)/(1-1/a)=(a+1)/(a-1)=(a-1+2)/(a-1)=1+2/(a-1)令1/b=2/(a-1)则b→∞a=2b+11/x=a=2b+1所以原式=(1+1/b)^(2b+1)=[(1+1/b)^b]²*(1+1/b)(1+1/b)^趋于1(1+1/b)^b极限是e所以极限=...