已知limln(1+f(x))/x^2=2求limf(x)/x^2=?x-0x-0如果是用等价无穷小替换原理,那么分母的f(x)要趋于零,但是条件只是给出了X趋于零,

Question

已知limln(1+f(x))/x^2=2 求lim f(x)/x^2=?x-0 x-0
如果是用等价无穷小替换原理,那么分母的f(x)要趋于零,但是条件只是给出了X趋于零,

Answer 1

ln(1+f(x))~f(x)
limln(1+f(x))/x^2=2
ln(1+f(x))~2x^2~f(x)
lim f(x)/x^2=2