f(x)=1/2x²-ax+(a-1)lnx,a>1,x>0
求导
f'(x)=x-a+(a-1)/x=[x-(a-1)](x-1)/x
I)当1=0,且f'(x)不恒为0,f(x)在x∈(0,+∞),单调递增
III)当a>2,时
x∈(0,1),f'(x)>0,f(x)单调递增
x∈(1,a-1),f'(x)
f(x)=1/2x²-ax+(a-1)lnx,a>1,x>0
求导
f'(x)=x-a+(a-1)/x=[x-(a-1)](x-1)/x
I)当1=0,且f'(x)不恒为0,f(x)在x∈(0,+∞),单调递增
III)当a>2,时
x∈(0,1),f'(x)>0,f(x)单调递增
x∈(1,a-1),f'(x)