已知(x^2 y)dx (x y^3)dy为函数u的全微分

xy-eˆ(2x)=siny两边对x求导,得y+x(dy/dx)-2eˆ(2x)=(cosy)*(dy/dx)(x-cosy)*(dy/dx)=2eˆ(2x)-ydy/d

解析2xdx+ydx+xdy+3y²dy=0(2x+y)dx+(x+3y²)dy=0(2x+y)dx=-(x+3y²)dydy/dx=(2x+y)/-(x+3y²

x^2*dy/dx=xy-y^2dy/dx=y/x-y^2/x^2u=y/xy=xuy'=u+xu'代入：u+xu'=u+u^2xu'=u^2du/u^2=dx/x-1/u=lnx+lnCCx=e^(

对y的偏导就是4xy+x^2,对y积分得到2xy^2+x^2y+g(x)对x的偏导就是2y^2+2xy+3x^2,对x积分得到2xy^2+x^2y+x^3+h(y)综合得到2xy^2+x^2y+x^3

dy/dx=(xy+3x-y-3)/(xy-2x+4y-8)=(x-1)(y+3)/(x+4)(y-2)再问：然后呢？再答：(y-2)dy/(y+3)=(x-1)dx/(x+4)已经是变量分离方程，两

-xy（x^2y^5-xy^3-y)=-(xy^2)^3+(xy^2)^2+xy^2=-(-2)^3+4-2=8+4-2=10

y跟x是成函数关系吧那么第一个就是求导了两边同时对x求导令dy/dx为a则6a/6y=3y+3xaa=3y^2/1-3xy第二问就是再导多一次令d^2y/dx^2=bby-a^2/y^2=3a+3a+

令z=1/x,则dx=-x²dz代入原方程得(x²y³+xy)dy=-x²dz==>dz/dy+y/x=-y³==>dz/dy+yz=-y³

y'e^y+e^x-y²-2xyy'=0y'=(e^x-y²)/(2xy-e^y)即：dy/dx=(e^x-y²)/(2xy-e^y)祝你开心!希望能帮到你,如果不懂,请

(6xy^2-y^3)dx+(6x^y-3xy^2)dy=d(3x^y^-xy^3),∴原式=（3x^y^-xy^3)|,=(9x^-7x)|=9*7-7=56.再问：原式==（3x^y^-xy^3)

令y/x=u,dy=u+xdu,原方程化为:u+xdu/dx=x/(u^2)+u,即du/dx=1/(u^2)通解为:y=x*[(3x+3c)^(1/3)]

∵dy/dx=(x+y^3)/(xy^2)==>xy^2dy=(x+y^3)dx==>y^2dy/x^3=dx/x^3+y^3dx/x^4(等式两端同除x^4)==>d(y^3)/(3x^3)+y^3

别人一般问一道题,你一下子5道?我给你个提示：1.所有5道题全部可以化成y'=f(y/x)的形式.比如5：:y’=√(1-y^2/x^2)+y/x2.设y/x=uy=xuy'=u+xu',代入：u+x

x²y+2xy+3=-18两边同时对x求导得：2xy+x²dy/dx+2y+2xdy/dx+0=02xy+2y+(x²+2x)dy/dx=0(x²+2x)dy/

令z=1/x,则dx=-x²dz代入原方程得(x²y³+xy)dy=-x²dz==>dz/dy+y/x=-y³==>dz/dy+yz=-y³

2(x+xy)-[(xy-3y)-x]-(-xy)=2x+2xy-xy+3y+x+xy=3x+3y+2xy=3（x+y）+2xy=3*（-2）+2*3=0

这么难啊

∵x-y=4xy，∴2x+3xy-2yx-2xy-y=2(x-y)+3xyx-y-2xy=8xy+3xy4xy-2xy=112．故答案为：112．

令Q=xy²+y³,P=-(x³+x²y)∵αQ/αx=y²,αP/αy=-x²∴由格林定理,得∫(xy²+y³)dy-

原式=-xy²（x²y^4-xy²-1）∵xy²=-2原式=2（（-2)²-（-2）-1）=10