Well, strange in my opinion, hah. This is actually for my differential equations class...but I figure it's stuff that I should've already learned. Now for something that we are doing, the number of roots are important. So upon factoring something like (m^4 - 2m^2), it goes to m^2(m^2 - 2) So the roots are supposedly, 0, 0, -2 and 2. Now WHY ON EARTH do we include zero twice? My teacher said that it is crucial to do so. This doesn't really make sense...it's the same number...isn't this redundant? It makes a huge difference in the DE application...so there must be something to this. If anybody could please explain. Thank you.