Mathematics

Hi everyone, I'm having a little trouble using the xcorr instruction in matlab, and honestly I don'y quite get how it works. Now I know that when you type l=xcorr(u,v) it creates a new vector that containg the entire correlation sequence. But say I want to calculate [y(t-1)*y(t-2)]/N, whete t=1,...,N. How do I do that using the xcorr instruction? Thanks, PM

In classical maths from Euclid believed that a triangle is 180º and that in 1 point only can travel a parallel to other. – http://en.wikipedia.org/wiki/Parallel_postulate So determine that “At most one line can be drawn through any point not on a given line parallel to the given line in a plane” Lately Non-Euclidean geometry says that “Either there will exist more than one line through the point parallel to the given line or there will exist no lines through the point parallel to the given line” – http://en.wikipedia.org/wiki/Non-Euclidean_geometry#History According to this new geometry (has more that a century), by a point can exist more that one line, so acc…

Going to throw my laptop out of the window soon. Don't think it will help though. Little things are tripping me up, and I can't get answers for them anywhere I search. I have a standard deviation value, I have a graph with a point plotted. How to I add an error bar to this? I mean, the SD value is 0.9. Do I draw the bar going 0.9 above and 0.9 below the point? Or do I have the point in the middle of that error margin, and the error bar going 0.45 above and below my point on the graph? I hope it's the latter of the two, or else I have to draw this graph for the 100th time because it's not big enough for these error bars.

I'm looking for a book or some kind of course on "wave mathematics". I'm familiar with basics, like wavelength, frequency, amplitude, interferrence and all that, but I want to further improve my understanding of this subject.

Manipulating Euler's equation I got this equation (-1)^(1/pi)*e^i=1^(1/pi) To the best of my knowledge this equation is correct. If it is, why would Google calculator give a complex value for for the left side of the equation when the actual value should be 1.

My take on the original proof by Euclid, which shows that there are infinitely many prime numbers. A good introductory proof I believe... Now questions regarding the nature and methodology of the proof... What demonstrations are involved in this? I'd like to think: proof by exhaustion (whole) and proof by absurdity (2.B). Can case 2B also be shown as a proof by contradiction, where it implies K is not in L (a direct contradiction of the assumption)? BTW, I'm a student. When I first encountered this theorem, this was my first real exposure to an elementary proof and I found it beautiful. I wanted to paraphrase it so that things would be a little more obvious…

In your opinion, what equations, solutions, or sets are the most elegant math equations ever solved or conceived of? Personally, I like Euler's identity. That is, e^(i*pi) +1 = 0. The way it is proven is also something to marvel at too, since it comes directly out of complex analysis.

What happens to the number zero on the brink and inside a black hole? Or does a black hole not discriminate information? Or perhaps regarding zero "non-information"? And if zero is not non-information, why is it not?

Hi , I was thinking about this , as you know calculus was used many years before the explicit work of both Newton and Leibniz , it was used the hard way , unrecognized , scattered and buried among unrelated formulas and topics. The golden question is ; what if there is another revolutionary mathematical "principle" "tool" "method" (call it what you want) lurking on the orizon and living incognito inside the works of mathematicians ?! Do you have some insights on what would it be like ? Everyone who works with math , experiences sometimes the "aha" feeling when meeting with some beautiful pattern or similarity or a connection between unrelated stuffs , that would be a grea…

what do you mean by iota? What is (i)^(1/2)? What is the position of iota in counting dimension? Where is the position of iota

Hello, all! I have recently developed an interest in mathematics, and I was wondering where I should begin. Unfortunately, my grasp on the fundamentals is rudimentary at best, and I'm looking to sharpen what skills I have and develop those I don't. I would like something appropriate for self-teaching. (But if I reach an impediment too great to be overcome alone, I can find help.) The branches (?) I'm targeting are algebra and geometry, though books about trigonometry, calculus, and others are welcome, too, as I would like to at least become comfortable with calculus. Thanks in advance, guys (and gals)!

The next situation is presented 2 big circles (blue ones) are rotating in different directions. The left one is rotating clockwise and the right one rotates counter clockwise. Inside the 2 big circles, 2 small circles (pink ones) are embedded. The big circles rotate at constant speed, so the small circles also rotate at constant speed. A straight line is "connected" from the center of one small circle to another while the circles are rotating. Having in mind that the straight line must has a constant length.. The questions are: 1) What would be the separation (in millimeters) from the center of the big circle to the center of the small circle? Note: I assume…

<Date 2150-13-0> Ok you know that SquareRoot(-1)=iota Can you please know that log(-1)=jeota

We know that by adding 3 by 3 times 3+3+3 or 3*3=9 We also know that by multiplying 3 by 3 times 3*3*3 or 3^3=27 what will be next level? 3^(3^3) or (3^3)^3 or what? this was upper level of ^ which we dont know? Now can you tell me Lower level of + Because upper level of + is * and upper level of * is ^ Lower level of ^ is * and lower level of * is + '----- Is upper level of ^ is superpower Is Lower level of + is subplus '------ Although we know that there is nothing in maths like this but can you please have knowledge!!! Solve This complex complexity

Dear Science Forums members, I have a tricky problem that I hope one of you can help me with. (It's for a personal project, nothing to do with school.) I'm looking for a closed-form expression for the sum of the first through m-th terms of a combinatorial number. For those of you unfamiliar with combinatorial numbers, here's some useful reading: http://en.wikipedia.org/wiki/Combina..._number_system Basically, the idea is this: for any non-negative integers k, and b, we can express the value of b as a sum of k terms of the form (r1 choose k)+(r2 choose k-1)+(r3 choose k-2)...(rk choose 1). For every t and s where t and s are non-negative integers such that t<s, it wi…

Number of possibilities, triangles with different colors? Hi everybody, I'm doing research with triangles. Here's my problem: Imagine three points (a triangle). There are four possible colors to color an edge with. You can use the colors as often as you'd like. How many different triangles can you form? The answer isn't as straightforward as 4^3, because a rotation is not a "new triangle". My answer by just writing all 4^3=64 possibilities down and the categorize them gave 16 different possibilities. Would any of you know how to theoretically get this number instead of just writing them all down? The attachement shows all 16 triangles (in my case i swapped the four…

Hello, I'm almost 30 and I've decided to quit my job in order to pursue mathematics full time. Basically, I want to discover something that will make me famous and put my name in math books around the world. That's it in a nutshell. Now, I'd like you to give me some much needed insight into how realistic my new found dream is. Please understand that I've had some talent in math as a kid, which was a decade ago, and that in order to realize my dream I'll be living and breathing mathematics, all day, everyday, for the rest of my life. Thanks in advance for any insight you're willing to share with me.

P Versus NP Hodge Conjecture Poincare Conjecture Reimann Hypothesis Yang-Milis existence and mass gap Navier-Stokes existence and smoothness Birch and Swinnerton-Dyer conjecture (which i thought was already proved) so far the only 1 that was solved is Poincare Conjecture by Gregori Pearlman..... what are the chances of some genius mathematician or mathematicians solving the other ones

Can anyone tell me what is the difference between Root mean square deviation and standard deviation?

Just started to learn a bit of set theory, and was hoping someone could aid my understanding of power sets. As i understand it a power set is the set of all subsets within a given set. This includes the null set - easy enough. It also includes each of the elements within the set. Isn't this saying that each element of a set is also a subset of the set? It then includes the set of all elements. Since all the elements are the set, isn't this saying that set A is a subset of itself? Hopefully i'm just confusing an element with a subset, but any help is appreciated. P.S. And am i right in thinking there can be no subsets of the power set, only elements?

Just came across an idea out of curiosity, so albeit this discussion will be quite "soft". When we differentiate a single-variable function, we are intuitively finding the slope of the tangent line given an arbitrary point. What if we instead observe the slope of the line perpendicular to the tangent? For example, the linear function [math]f(t)=2t[/math]. Differentiating yields [math]\frac{d}{dt} 2t=2[/math]. At any given point in the function, the slope of the tangent line is 2. However, if we looked at the slope of the line perpendicular to the tangent, we'd come across [math]-\frac{1}{2}[/math]... Because at any given point on the function, the slope perpendicu…

Hello to All, This is a continuation of the post "Travelling Salesman Problem" given by me in Appplied Mathematics section. I am giving a very simple explanation of the algorithm so that it becomes easier to understand. I did not see that postings could be made in the Mathematics section. That is why I am posting here. The main advantage of this approach is that the exact solution can be obtained for "complete" graphs in polynomial time. ( Please note that the word "complete" which is mentioned here is the same mathematical term used in graph theory ). I tried out the "complete" graph examples in the textbook using pen and paper and they are…

Any idea about Pascal's Triangle?

Hello! Since I haven't solved any examples using functions in a while, it's hard for me to solve this example. It would be really nice if someone could help me in some way and explain how i works.

I would like to ask you some questions. 1) I've a closed curve (for example an ellipse, which may represent the contour of an object) represented by the set of its (known) points. I need to find the equation of that curve to pass through all and every point (exact fit). I think that to do this I need a polynomial whose grade is equal to the number of points less 1. Something like this: a0+a1 x1+a2 x1^2+ ...+ an x1^n = y1 a0+a2 x2+a2 x2^2+ ...+ an x2^n = y2 ... a0+a2 xn+a2 xn^2+ ...+ an xn^n = yn This argument is right? Do you have suggestions (or anything else relevant) for me in this regard for which is the best way to solve my problem? This equation …