问题
选择题
函数f(x)=x(x-1)(x-2)…(x-50)在点x=0处导数为( )
A.0
B.502
C.100
D.50!
答案
f′(x)=x′[(x-1)(x-2)…(x-50)]+x[(x-1)(x-2)…(x-50)]′
=[(x-1)(x-2)…(x-50)]+x[(x-1)(x-2)…(x-50)]′
∴f′(0)=(-1)(-2)…(-50)=50!
故选D
函数f(x)=x(x-1)(x-2)…(x-50)在点x=0处导数为( )
A.0
B.502
C.100
D.50!
f′(x)=x′[(x-1)(x-2)…(x-50)]+x[(x-1)(x-2)…(x-50)]′
=[(x-1)(x-2)…(x-50)]+x[(x-1)(x-2)…(x-50)]′
∴f′(0)=(-1)(-2)…(-50)=50!
故选D