答:
f(x)=xlnx,g(x)=x^3+ax^2-x+2
1)
求导得:g'(x)=3x^2+2ax-1
g(x)单调减区间为(-1/3,1)
表明x=-1/3和x=1是g'(x)=0的解
x=1代入得:3+2a-1=0
解得:a=-1
所以:g(x)=x^3-x^2-x+2,g'(x)=3x^2-2x-1
点P(-1,1)处:g(-1)=-1-1+1+2=1,g'(x)=3+2-1=4
点P在g(x)上,所以切线方程为:y-1=4(x+1),y=4x+5
2)
2f(x)
答:
f(x)=xlnx,g(x)=x^3+ax^2-x+2
1)
求导得:g'(x)=3x^2+2ax-1
g(x)单调减区间为(-1/3,1)
表明x=-1/3和x=1是g'(x)=0的解
x=1代入得:3+2a-1=0
解得:a=-1
所以:g(x)=x^3-x^2-x+2,g'(x)=3x^2-2x-1
点P(-1,1)处:g(-1)=-1-1+1+2=1,g'(x)=3+2-1=4
点P在g(x)上,所以切线方程为:y-1=4(x+1),y=4x+5
2)
2f(x)