(1) f'(x)=1/x点P(m,f(m))处的切线方程为y=x,斜率＝1所以,f'(m)=1,即,1/m=1解得,m＝1又,f(m)=m,即,n+lnm=m解得,n=1所以,g(x)=x-1/x-2lnxg'(x)=1+1/x²-2/x=(x²-2x+1)/x²=(x-1)²/x²当x≥1时,...