[题目]定积分 (int )_(0)^pi xcos xdx= __

[题目]计算定积分: (int )_(-dfrac {pi )(2)}^dfrac (pi {2)}dfrac (1)(2)xcos xdx.

定积分(int )_(0)^dfrac (pi {2)}(e)^xsin xdx的值是(int )_(0)^dfrac (pi {2)}(e)^xsin xdx

定积分int_(0)^(pi)/(4)sec^2xdx=11.（填空题，5.0分）定积分$\int_{0}^{\frac{\pi}{4}}sec^{2}xdx=

(int )_(0)^dfrac (pi {2)}(e)^2xcos xdx

(int )_(0)^dfrac (pi {2)}(e)^2xcos xdx; ;

(6) (int )_(0)^dfrac (pi {2)}(sin )^2xcos xdx;

求 (int )_(0)^dfrac (pi {2)}(e)^2xcos xdx求

计算定积分 int_(0)^pi sin xdx= ( )A. 1B. -1C. 2D. -2

对于定积分int0pi xsin xdx，使用分部积分法则时，应设（）A. u=x，dv=$\sin xdx$B. u=$\sin x$，dv=$xdx$C.

7.计算下列定积分:-|||-(1) (int )_(0)^1x(e)^-xdx ;-|||-(2)(int )_(1)^xxln xdx;-|||-(3) (