int (e)^-2xsin dfrac (x)(2)dx;

求 int(cos2x)/(cos^2xsin^2x) dx 。求$ \int\frac{cos2x}{cos^2xsin^2x} dx $。

int dfrac ({e)^x}({2)^x}dx;

int t(e)^-2tdt.-|||-.int (ln )^2xdx-|||-.int xsin xcos xdx.-|||-15. int (x)^2(co

( 单选题 ) int dfrac ({e)^x}(1+{e)^2x}dx=_________int dfrac ({e)^x}(1+{e)^2x}dx=int

(int )_(-infty )^+infty (x)^2(e)^-a(x^2)dx=dfrac (1)(2)sqrt (dfrac {pi )({a)^3}}

lim_(xto0)(2xsin x)/(e^x^(2)-1)-2=____填空题（共15题，30.0分）33. (2.0分) $\lim_{x\to0}\fr

(9) int dfrac (x{e)^arctan x}({(1+{x)^2)}^dfrac (3{2)}}dx ;

int dfrac (ln tan x)(cos xsin x)dx

(int )_(1)^(e^2)dfrac (ln x)(sqrt {x)}dx= __

(int )_(e)^+infty dfrac (dx)(x{ln )^2x}= __