f-1(x)=log3(3^x+1)F(x)=f-1(2x)-f(x)=log3(3^2x+1)-log3(3^x-1)=log3[(3^2x+1)/(3^x-1)]令3^x=k则[(3^2x+1)/(3^x-1)]=(k²+1)/(k-1)=(k²-k+k-1+2)/(k-1)=k+1+1/(k-1)=(k-1)+1/(k-1)+23^x=k＞0k-1>-1但log3...