1.
h(x)=f(x-1)-g(x)=lnx-(1/2)ax²-2x,x>0
h'(x)=1/x-ax-2=-(ax²+2x-1)/x
i)当a=0,h'(x)=-(2x-1)/x
知x∈(1/2,+∞),h'(x)