1)f'(x)=1/x
g(x)=lnx+1/x
g'(x)=1/x-1/x^2=(x-1)/x^2=0,x=1
x0,单调增区间
最小值在X=1时,g(1)=1
2)g(1/x)=-lnx+x
y=g(x)-g(1/x)=2lnx+1/x-x
y'=2/x-1/x^2-1=(2x-1-x^2)/x^2=-(x-1)^2/x^2