Well I need to find the phase graph of the next system of ode: dx2/dt=-4x1 dx1/dt=x2 now i know the curves of x2 as a function of x1 are ellipses, but in what direction. I mean obviously i need to check dx2/dx1, and from this find if x2 is decreasing or increasing, so for the first quadrant obviously it goes clockwise cause dx2/dx1<0 so x2 in this quadrant is decreasing, the same analysis i did with the other quadrants but shouldn't it have a consistent direction, I mean from my analysis not every part of the ellipse in every quadrant moves clockwise. can this be ok? or am i way off here? thanks in advance.