设(x)=((2-x))^tan dfrac (pi {2)x},(dfrac (1)(2)lt xlt 1),求(x)=((2-x))^tan dfrac (pi {2)x},(dfrac (1)(2)lt xlt 1)。

求极限 lim _(xarrow 1)(1-(x)^2)tan dfrac (pi )(2)x

lim _(xarrow 1)(1-x)tan dfrac (pi x)(2)-|||-__..

证明:当 lt xlt dfrac (pi )(2) 时, tan xgt x+dfrac (1)(3)(x)^3.

设(X,Y)的分布函数为(x,y)=dfrac (1)({pi )^2}(dfrac (pi )(2)+arctan dfrac (x)(2))(dfrac (

(8) lim _(xarrow dfrac {pi )(2)}dfrac (tan x)(tan 3x)

(8) lim _(xarrow dfrac {pi )(2)}dfrac (tan x)(tan 3x)

1357.已知 tan x=1, in (dfrac (pi )(2),dfrac (3pi )(2)), 则 =-|||-

(sin x)=dfrac (1)({cos )^2x} in (0,dfrac (pi )(2)),则(sin x)=dfrac (1)({cos )^2x}

设=(int )_(-dfrac {pi )(2)}^dfrac (pi {2)}dfrac (sin x)(1+{x)^2}(cos )^4xdx, =(in

lim _(xarrow dfrac {pi )(2)}((sin x))^tan x=（ ）（ ）