问题 填空题

设m∈R,已知函数f(x)=-x2-2mx2+(1-2m)x+3m-2,若曲线y=f(x)在x=0处的切线恒过定点P,则点P的坐标为______.

答案

f(x)=-x3-2mx2+(1-2m)x+3m-2,f′(x)=-3x2-4mx+(1-2m).

因为f(0)=3m-2,f′(0)=1-2m,

所以曲线y=f(x)在x=0处的切线方程为y-(3m-2)=(1-2m)(x-0),

即m(2x-3)+(y-x+2)=0.

由于

2x-3=0
y-x+2=0
x=
3
2
y=-
1
2

故切线恒过定点P(

3
2
,-
1
2

故答案为:(

3
2
,-
1
2
).

单项选择题
单项选择题