来自蒋盛益的问题
【f(x)=g(x)/x,x≠0;0,x=0,其中g(x)可导,且在x=0处二阶导数g''(0)=3,且g(0)=g'(0)=0,试求f'(0)】
f(x)=g(x)/x,x≠0;0,x=0,其中g(x)可导,且在x=0处二阶导数g''(0)=3,且g(0)=g'(0)=0,试求f'(0)
1回答
2020-12-25 18:27
【f(x)=g(x)/x,x≠0;0,x=0,其中g(x)可导,且在x=0处二阶导数g''(0)=3,且g(0)=g'(0)=0,试求f'(0)】
f(x)=g(x)/x,x≠0;0,x=0,其中g(x)可导,且在x=0处二阶导数g''(0)=3,且g(0)=g'(0)=0,试求f'(0)
f'(0)=lim[x→0][f(x)-f(0)]/x
=lim[x→0][g(x)/x-0]/x
=lim[x→0]g(x)/x²
洛必达法则
=lim[x→0]g'(x)/(2x)
=(1/2)lim[x→0][g'(x)-g'(0)]/x
=(1/2)g''(0)
=3/2
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