来自牛培峰的问题
已知函数f(x)=Inx-1/2ax^2-2x(a
已知函数f(x)=Inx-1/2ax^2-2x(a
1回答
2020-08-21 17:14
已知函数f(x)=Inx-1/2ax^2-2x(a
已知函数f(x)=Inx-1/2ax^2-2x(a
1)f′(x)=1/x-ax-2,若f(x)存在单调递减区间,则在(0,+∞)上f′(x)≤0,∴a≥1/x²-2/x=(1/x-1)²-1≥-1即a∈[-1+∞)2)若a=-1/2,f(x)=-1/2x+b可化为lnx+1/4x^2-3/2x=b令g(x)=lnx+1/4x^2-3/2x,...