=lime^[(a^xlna+b^xlnb+c^xlnc)/3] =[e^(lna+lnb+lnc)]^1/3 求解這一步是怎麼來的………

=lime^[(a^xlna+b^xlnb+c^xlnc)/3] =[e^(lna+lnb+lnc)]^1/3 求解這一步是怎麼來的………

令y=e^(a^xlna+b^xlnb+c^xlnc)/3那麼lny=(a^xlna+b^xlnb+c^xlnc)/3兩邊取極限的lim(lny)=(lna+lnb+lnc)/3而且原來的極限=lim(e^lny)=e^(limlny)=e^[(lna+lnb+lnc)/3]=[e^(lna+lnb+lnc)]^1/3