What method should I use to solve the equation $\displaystyle (x+y)dx-(x-y)dy=0$ ? It looks like I might need to find an integrating factor to make it exact, but maybe there's a simpler way?
4. Hi. Can't think of one. Standard approach for these is to let $\displaystyle y=vx$, get it in terms of x and v. Separate, integrate, then back substitute v=y/x. Maybe another way though.