设a,b为常数,且 lim _(xarrow infty )(sqrt [3](1-{x)^6}-a(x)^2-b)=0, 则 a= __ b= __ .

5 设a,b为常数，且lim_(xtoinfty)(sqrt[3](1-x^6)-ax^2-b)=0，则a=____ b=____5 设a,b为常数，且$\li

已知lim _(xarrow +infty )(x)^a[ sqrt ({x)^2+1}+sqrt ({x)^2-1}-2x] =bneq 0 x]=b≠0，则

[例6] 设函数 (x)=dfrac (x)(a+{e)^bx} 在 (-infty ,+infty ) 内连续,且 lim _(xarrow infty )f

6、极限 lim _(xarrow +infty )(sqrt ({x)^2+x}-sqrt ({x)^2+1})= () 。(较难)-|||-A、0 B、 d

lim _(xarrow infty )(3x-sqrt (a{x)^2-x+1})=dfrac (1)(6), 则 a=

设 lim _(xarrow 0)dfrac (ln (1+x)-(ax+b{x)^2)}({x)^2}=2, 则设 lim _(xarrow 0)dfrac

lim _(xarrow 0)dfrac (xtan x)(sqrt {1-{x)^2}-1}=________.________.

(B) lim f(x)=0.-|||-(C) lim _(xarrow 1)f(x)=infty . D)limf(x)不存在,且 lim _(xarrow

lim _(xarrow +infty )x(sqrt ({x)^2+1}-x)；；

lim _(xarrow infty )dfrac (6{x)^2+2}({x)^2}=A.6B.2C.3D.0A.6B.2C.3D.0