5.已知 lim _(xarrow 2)dfrac ({x)^2-ax+b}(2-x)=1 ,试求a与b的值.

2.已知 lim _(xarrow 1)dfrac ({x)^2+ax+b}(1-x)=1, 求常数a与b的值...

（3）已知lim _(xarrow 2)dfrac ({x)^2+ax+b}({x)^2-x-2}=2-|||-__，求a，b.（3）已知，求a，b.

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

[题目]若 lim _(xarrow infty )(dfrac ({x)^2+1}(x+1)-ax-b)=0, 求a,b的值.

(13)设 lim _(xarrow 1)dfrac ({x)^3+ax-2}({x)^2-1}=2 求a的值。

5.求极限 lim _(xarrow 0)dfrac ({tan )^2x-(x)^2}({x)^2(tan )^2x}

8.已知 lim _(xarrow infty )dfrac ((a-1){x)^2-2x+3}({x)^2+x-5}=0 ,求a的值.

5.单选题极限lim _(xarrow dfrac {pi )(2)}((1+cot x))^tan x=( )A.1B.eC.lim _(xarrow dfr

)求下列极限:-|||-(1) lim _(xarrow 1)dfrac ({x)^2-x+1}({(x-1))^2} =-|||-(3) lim _(xarr

(3)lim _(xarrow 1)dfrac (ln (2-x)arctan x)(sin ({x)^2-1)}(3)