3xy^2dy=(2y^2-x^3)dx
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y(x^2-xy+y^2)dx=-x(x^2-xy+y^2)dy,当y≠0时,x^2-xy+y^2=(x-0.5y)^2+3/4y^2>0,两边约去此式,得ydx=-xdy,-dx/x=dy/y,易得
y(x^2-xy+y^2)dx+x(x^2-xy+y^2)dy=0(x^2-xy+y^2)(dxy+dxy)=0(x^2-xy+y^2)*2dxy=02dxy=0(1)或者x^2-xy+y^2=0(2
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^(
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
结果当然可以写成:|(y-2x)^3=C(y-x)^2,C为待定常数,解曲线为下面是具体求解过程:
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
(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)
答:dy/dx=1+x+y^2+xy^2y'=(1+x)(1+y^2)y'/(1+y^2)=1+x(arctany)'=1+x积分得:arctany=x+x²/2+Cy=tan(x+x
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
y^2=(xy-x^2)dy/dxy^2/x^2=(y/x-1)dy/dxy/x=udy=udx+xduu^2=(u-1)(u-xdu/dx)u^2/(u-1)=u-xdu/dxxdu/dx=u-u^
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
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
显然不是啊
2x+2ydy/dx-y-xdy/dx+3=0dy=(2x-y+3/x-2y)dx
令y=xuy'=u+xu'代入方程:u+xu'=u^2/(u-1)xu'=u/(u-1)du(u-1)/u=dx/xdu(1-1/u)=dx/x积分;u-ln|u|=ln|x|+C1e^u/u=Cxe
你要求什么?