已知曲线f(x)=x n+1 (n∈N * )与直线x=1交于点P,若曲线y=f(x)在点P处的切线与x轴交点的横坐标为
1个回答

由题意可得P(1,1)

对函数f(x)=x n+1求导可得,f′(x)=(n+1)x n

∴y=f(x)在点P处的切线斜率K=f′(1)=n+1,切线方程为y-1=(n+1)(x-1)

令y=0可得, x n =

n

n+1

∴x 1x 2…x 2011=

1

2 •

2

3 •

3

4 …

2011

2012 =

1

2012

∴log 2012x 1+log 2012x 2+…+log 2012x 2011=log 2012(x 1x 2…x n

= log 2012

1

2012 =-1

故选B