3.问a,b为何值时,有极限-|||-lim _(xarrow 0)(dfrac (sin 3x)({x)^3}+dfrac (a)({x)^2}+b)=0-|||-成立.

(3) lim _(xarrow 0)dfrac (tan x-sin x)({sin )^3x}

(3) lim _(xarrow 0)dfrac (tan x-sin x)({sin )^3x};

求极限: lim _(xarrow 0)((1+2x))^dfrac (1{sin 3x)}=

极限lim _(xarrow 0)dfrac (tan 3x)(x)=__________极限__________

3.lim _(xarrow 0)dfrac (tan x-sin x)({sin )^3x}.3..

(5) lim _(xarrow 0)dfrac (tan x-sin x)({sin )^3x}

(3) lim _(xarrow 0)dfrac (1-cos 3x)({sin )^2x}

求极限：lim _(xarrow 0)dfrac (3x)(1-sqrt {1+sin x)}求极限：

求极限 lim _(xarrow 0)dfrac (ln (1+{x)^2)-ln (1+(sin )^2x)}(x{sin )^3x}

3.计算下列极限:-|||-(1) lim _(xarrow 0)(x)^2sin dfrac (1)(x); ()-|||-__