=xarcsin dfrac (x)(2)+sqrt (4-{x)^2}

3.设 =xarcsin dfrac (x)(2)+sqrt (4-{x)^2} 则 dy= __ 。

求下列不定积分int dfrac ({x)^2}(sqrt {4-{x)^2}}dx求下列不定积分

(int )_(-2)^2(sqrt (4-{x)^2}+x)dx 等于(　　)等于(　　) A. 0

(({int )_(-2)^2}(x-2)sqrt (4-{x)^2}dx

(int )_(-2)^2(x-2)sqrt (4-{x)^2}dx

lim _(xarrow 4)dfrac (sqrt {2x+1)-3}(sqrt {x-2)-sqrt (2)}=..

(4) =dfrac (x)(sqrt {1-{x)^2}}

(2) (int )_(-2)^2((x)^3(cos )^5x+sqrt (4-{x)^2})dx=

（21）lim _(xarrow 4)dfrac (sqrt {2x+1)-3}(sqrt {x-2)-sqrt (2)}（21）

=dfrac (x)(sqrt {1-{x)^2}}，则=dfrac (x)(sqrt {1-{x)^2}}=_________.，则=_________.