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问题: 导数定义题

已知f'(0)=2,则lim[f(3h)-f(-h)]/h=?(h→0)

解答:

lim<h->0>[f(3h)-f(-h)]/h
=lim<h->0>{[f(0+3h)-f(0)]-[f(-h)]-f(0)}/h
=3*lim<h->0>[f(0+3h)-f(0)]/(3h)+lim<h->0>[f(0-h)-f(0)]/(-h)}
=3f'(0)+f'(0)
=4f'(0)
=4*2
=8