设a≥0,f(x)=x-1-(lnx)^2+2alnx (x>0).令F(x)=xf'(x),讨论F(x)在(0,正无穷
0)所以F(x)=xf'(x)=x+2a-2lnx(x>0)所以F'(x)=1-(2/x)=0得x="}}}'>