m文件如下:fun_u=@(x,y) -2*x*y^4/(y^3*(y-3*x^2));[x,y]=ode45(fun_u, 0:0.1:20, 1);[x,y]plot(x,y);xlabel('x');ylabel('y');y=dsolve('Dy=-2*x*y^4/(y^3*(y-3*x^2))','x')结果: y = 0 2*x^2 x^2*z1z1 = RootOf(z^3 - z*exp(2*C9 - 4*log(x)) + 2*exp(2*C9 - 4*log(x)), z)
y= 3x+4
dy = 3dx
dx=3