Recent content by mathphys

the right hand side of your equation is positive right?, what is the minimum value of x for which this is posible? and the corresponding value of y? this is the vertex. Now rebember that p=1 is the distance from the vertex to the focus and that you have and horizontal parabola.

You can try this. You have 3 set A={2,4,8..} n(A)=6 B={3,9,27,.} n(B)=5 C={5,25} n(C)=2 the total number of divisors are n(A)+n(B)+n(C)+ n(AXB)+ n(AxC)+ n(BXC)+ n(AxBxC) where AXB are number formed by multipliying each element of A for each element of B, and taking into...

mm The simplest way in which I had thought to attack the problem was to assume that the superpostion principle holds anyway, in the following sense: My Ansatz is y(x)=y0(x)+y1(x) where y0 is the solution to L(y(x))=my(x)^n and ( n not 1 nor 0, sad) y1 to L(y(x))=f(x)...

Thanks to you all. Yep, I understand that the "superposition principle" holds just for linear differential operators. What I'm looking for is a similar (or different) procedure that may be used for nonlinear differential equations. I've heard that there are "nonlinear superposition...

I have a naive question about nonlinear ODEs, supose I have one of such equations, and that it is homogeneous NL(y(x))=0, (1) and I know the solution. Then I want to solve the "associated" non-homogeneous equation NL(y(x))=f(x) (2) There is a method to attack this kind of...

I know that they're different things, strictly speaking, that was my point. It is just that some people was saying that they were the same, they were the same, they were the same, and i was trying to explain why they are not. I don't know, maybe in 'their Books' there is no distinction and this...

Yes, the edge is the envolvent, that was my point when i said 'or'. Yes, I know that an explotion is not the same thing that a sonic boom. My point there was that a shockwave is not a sonic boom,in a general sense. You may say ahh but the shockwave and the sonic boom are the same according to...

I know that this is a 'tenebrous' topic. :devil: . But let me explain with an example its motivation Sometime ago i read ( i promise to search the reference) a work that critiziced some 'vices' that sometimes affect scientific research (I've said "sometimes", and that they critiziced the...

You are right, it is just that in the context of euclidian geometry the premise that there is always a midpoint between two arbitrary points P, Q on a line segment implies that there are infinitely many points between them. That is what i found disconcerting as part of the proof...

Well, i actually meaned a field in these sense http://en.wikipedia.org/wiki/Scalar_field and this other one http://en.wikipedia.org/wiki/Vector_field What function U represents physically depends on the context, many phenomena may be described by the wave equation...

I see your point. It was just that your proof put in my mind the idea of the real line (because of the 'we can order ' (<--specially this one , it is and interesting issue how we can :biggrin:) and 'midpoint') and Dedekind cuts. Althought that is not high school euclidean geometry.:blushing:

I_0 is not equal to I_1 because the radius of the sphere is different in each case. In one case we have a radius given by R, and in the other one we have a smaller radius: 0.550R. You have the correct expression for w0 in your first post w0=2pi rad/T_0=2pi rad /27.7 days.

Let's say that f(x) is Riemann integrable, ok? EDIT: In some interval (a,b) You take the limit of a Riemann sum to obtain its integral, with all that this implies, not by summing up 'infinitesimals of certain form'.

Whoa!, nice applets, thanks astronuc.