f'(x)=x'(x-1)(x-2)(x-3)…(x-100)+x(x-1)'(x-2)(x-3)…(x-100)+…+x(x-1)(x-2)(x-3)…(x-100)'
=(x-1)(x-2)(x-3)…(x-100)+x(x-2)(x-3)…(x-100)+…+x(x-1)(x-2)(x-3)…(x-99)
后面每项都有x,所以x=0时都等于0
所以f'(0)=(-1)(-2)(-3)……(-100)=100 !
f'(x)=x'(x-1)(x-2)(x-3)…(x-100)+x(x-1)'(x-2)(x-3)…(x-100)+…+x(x-1)(x-2)(x-3)…(x-100)'
=(x-1)(x-2)(x-3)…(x-100)+x(x-2)(x-3)…(x-100)+…+x(x-1)(x-2)(x-3)…(x-99)
后面每项都有x,所以x=0时都等于0
所以f'(0)=(-1)(-2)(-3)……(-100)=100 !