y = x - (1)/(2) sin x,则 (dx)/(dy) = ____。A. $\frac{2}{2 - \cos y}$B. $\frac{2}{2
设 x = y^y,则 (dy)/(dx) = ____设 $x = y^y$,则 $\frac{dy}{dx} = \_\_\_\_$
(2)(dy)/(dx)+(y)/(x)=(sin x)/(x),y|_(x=pi)=1;(2)$\frac{dy}{dx}+\frac{y}{x}=\frac
齐次方程dfrac (dy)(dx)=f(dfrac (y)(x)),可以设dfrac (dy)(dx)=f(dfrac (y)(x)),则方程可以化为dfra
设DX=4,DY=1, P_(x,y)=0.6 ,则D(3X-2Y)=().A. 40B. 34C. 25.6D. 17.6
[例5] 设函数f(x,y)连续,则 (int )_(1)^2dx(int )_(x)^2f(x,y)dy+(int )_(1)^2dy(int )_(y)^4
dfrac (dy)(dx)=(x)^2+(y)^2 B . dfrac (dy)(dx)=(x)^2+(y)^2 C .dfrac (dy)(dx)=(x)^
设 iint_(D) f(x, y)dx dy = int_(0)^1 dx int_(0)^1-x f(x, y)dy,则改变其积分次序后为A. $\int_
微分方程((y)^2+2)dx+y((x)^2+1)dy=0的通解为( )((y)^2+2)dx+y((x)^2+1)dy=0((y)^2+2
下式中正确的是A.(X+Y)=DX+DY+2Cou(X,Y)B.(X+Y)=DX+DY+2Cou(X,Y)C.(X+Y)=DX+DY+2Cou(X,Y)D.(X