定理4等价无穷小替换定理) 设a~a,B~P/lim2,存在,则lim2=lim 证lim β_m/β.阝.a c βaa βmβ Im d c c定理4(等价无穷小替换定理) ~ , ~ lim , lim lim .             =   设  且 存在 则 证   lim lim( )         =         = lim lim lim lim .   =