设f(x)和g(x)在负无穷到正无穷上有定义,且满足下列条件:(1)f(x+h)=f(x)g(h)+f(h)g(x) (2)f(x)和g(x)在x=0处可导,且f(0)=g'(0)=0,g(0)=f'(0)=1,求f'(x)请大侠们帮
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设f(x)和g(x)在负无穷到正无穷上有定义,且满足下列条件:(1)f(x+h)=f(x)g(h)+f(h)g(x) (2)f(x)和g(x)在x=0处可导,且f(0)=g'(0)=0,g(0)=f'(0)=1,求f'(x)请大侠们帮
设f(x)和g(x)在负无穷到正无穷上有定义,且满足下列条件:(1)f(x+h)=f(x)g(h)+f(h)g(x)
(2)f(x)和g(x)在x=0处可导,且f(0)=g'(0)=0,g(0)=f'(0)=1,求f'(x)
请大侠们帮助小弟,
设f(x)和g(x)在负无穷到正无穷上有定义,且满足下列条件:(1)f(x+h)=f(x)g(h)+f(h)g(x) (2)f(x)和g(x)在x=0处可导,且f(0)=g'(0)=0,g(0)=f'(0)=1,求f'(x)请大侠们帮
一楼楼主回答的很精彩啊,可惜是.,哈哈.
这道题主要是考查导数的定义的应用!
正确答案是g(x)
正确答案如下:
f'(x)= lim [f(x+h)-f(x)]/[(x+h)-x]
h->0
= lim[f(x+h)-f(x)]/h
h->0
由于f(x+h)=f(x)g(h)+f(h)g(x)
所以上式还可以化为:
f'(x)= lim〔f(x)g(h)+f(h)g(x)-f(x)]/h
h->0
= limf(x)*[g(h)-1]/h + limf(h)g(x)/h
h->0 h->0
=limf(x)*[g(h)-g(0)]/h +limg(x)*[f(h)-f(0)]/h
h->0 h->0
=f(x)*g'(0)+g(x)*f'(0)
=g(x)