【113】交换积分次序int_(-(pi)/(4))^(pi)/(2)dthetaint_(0)^2costhetaf(rcostheta,rsintheta)rdr=____.

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=

设 M=int_(-(pi)/(2))^(pi)/(2) (sin x)/(1+x^2) cos^4 x dx，N=int_(-(pi)/(2))^(pi)/(

(4)int_((pi)/(4))^(pi)/(3)(x)/(sin^2)xdx;(4)$\int_{\frac{\pi}{4}}^{\frac{\pi}{3}

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

int_(0)^pi/2(cos x+2)dx=( ).A. $\pi+1$B. $\pi$C. 2D. $\pi/2+2$

267 累次积分 int_(-(pi)/(2))^(pi)/(2)dxint_(0)^sin x(x^2+ycosx)sqrt(1-y^2)dy=A. $\fr

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

46.【2020河南】计算定积分int_(0)^(pi)/(4)(1)/(cos^2)x+3dx.46.【2020河南】计算定积分$\int_{0}^{\fra

1.交换积分次序：int_(1)^2dxint_((1)/(x))^xf(x,y)dy.1.交换积分次序：$\int_{1}^{2}dx\int_{\frac{

计算定积分：int_(0)^dfrac(pi {2)}(|sin x-cos x|{d)x}．计算定积分：$\int_{0}^{\dfrac{\pi }{2}}