3.求下列极限:-|||-(1) lim _(xarrow 0)sqrt ({x)^2-2x+5} ;-|||-(4 lim _(xarrow 0)dfrac (sqrt {x+1)-1}(x) ;-|||-(2)lim(sin2α)^3;-|||-alpha arrow dfrac (pi )(4)-|||-(5) lim _(xarrow 1)dfrac (sqrt {5x-4)-sqrt (x)}(x-1) =-|||-(3) lim ln (2cos 2x);-|||--dfrac (pi )(6)-|||-(6) lim _(xarrow a)dfrac (sin x-sin alpha )(x-alpha ) =

求极限lim _(xarrow 0)dfrac (x)(sqrt {1-x)-1}= ()lim _(xarrow 0)dfrac (x)(sqrt {1-x)

8.计算下列极限：(1) lim _(xarrow 0)dfrac (sin 4x)(sqrt {x+1)-1}(1) lim _(xarrow 0)dfrac

(4) lim _(xarrow 0)dfrac (sqrt {x+1)-1}(x);

求下列极限.-|||-lim _(xarrow 0)dfrac ({e)^x-sqrt (x+1)}(x);

3.求极限 lim _(xarrow 1)dfrac (sqrt [3]{x)-1}(sqrt {x)-1}

lim _(xarrow 0)dfrac (sqrt {x+1)-1}(x)= () ． ．

15.计算下列极限:-|||-(1) lim _(xarrow 0)sqrt ({x)^2-4x+2} ;-|||-(3) lim _(xarrow 0)dfr

求下列极限:-|||-(6) lim _(xarrow +infty )(x)^dfrac (3{2)}(sqrt (x+2)-2sqrt (x+1)+sqrt

[例3]求极限 lim _(xarrow infty )dfrac (sqrt {4{x)^2+x-1}+x+1}(sqrt {{x)^2+sin x}}

求lim _(xarrow 3)dfrac (sqrt {x+1)-2}(x-3)求