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问题: 若F(X)为偶函数,且F'(0)存在,证明F'(0)=0

解答:

F'(0)
=lim(F(h+0)-F(0))/(h-0) h趋于0

=lim(F(h)-F(0))/h h趋于0

=-lim(F(-h)-F(0))/(-h) h趋于0

=-lim(F(-h+0)-F(0))/(-h-0) -h趋于0(=h趋于0)

=-F'(0)
2F'(0)=0
F'(0)=0