lim x→0 [sin6x+xf(x)]/x^3=0,求 lim x→0 [6+f(x)]/x^2

问题描述:

lim x→0 [sin6x+xf(x)]/x^3=0,求 lim x→0 [6+f(x)]/x^2

因为lim x→0 [sin6x/(6x)]=1
所以,
lim x→0 [sin6x+xf(x)]/x^3
=lim x→0 [6x+xf(x)]/x^3
=lim x→0 [6+f(x)]/x^2
=0