1、想必那个表示的是指数的意思
所以4x^3dx-4y^3dy=-4ydx-4xdy,有dy/dx=(x^3+y)/(y^3-x)
2、sinxdy+ycosxdx-(dx-dy)sin(x-y)=0
推出dy/dx=(sin(x-y)-ycosx)/(sinx+sin(x-y)).